I can't see the picture (the link requests a username & password) but here are some thoughts ...

For a less expensive option than large plants, have you considered bare root plants or small-pack plants? Several years ago I replaced a strip of lawn between a rock wall & the road with Veronica blue. I bought the plants from www.classygroundcovers.com. They also sell bare root plants and when they have a sale things can be pretty cheap. I think the Veronica were still $4 a plant, and I needed 75 of them (so definitely not cheap) but they have a lot of other options that are less expensive. Liriope & daylilies can be had for $0.87/plant if you get them in 50 plant bundles.

If that is too much money, then you are probably looking at seeds. I wouldn't waste money on the "meadow in a can" type things, they are not great because they aren't optimized for your soil & sun conditions. A mix of self-sowing perennials and annuals would probably work well. There are too many to suggest specifics, but if you narrow down your color preference for flowers + amount of sun + amount of rain + soil type (fast draining, heavy, dry, ?) then your list will get much shorter.

As for prepping the area ... the tarp or some clear plastic will work for now. I wouldn't plant anything until the Fall, mid summer is a bad time for most things to get started (even ivy). I'm not a fan of ivy personally. It is green most of the year but it gets thick enough to be great cover for mice (or rats) and I'm always a little freaked out by it. It can be invasive and it isn't a food source for much of anything - flowers like echinacea & coreopsis will make seeds that birds love.

You will have to pull weeds the first couple years, but it will get better/easier as your new plants take over.

One last thought ... what about ornamental grasses for that area? This thread has some info on buying & starting seeds for those:

Here is a link that might be useful: GardenWeb Forum Discussion on Orn Grass Seeds

I had the same problem with the photo link.

I agree with pam29011 that the "meadow in a can" isn't the best idea. Certainly you won't have much luck tossing the seeds on top of the soil.

Whatever you plant, you'll still need to weed. Mulch helps prevent many weed seeds from sprouting, and also keeps the soil moist (your plants grow faster and you don't have to water as often). There are alternatives to buying expensive mulch. For example, you can mulch with grass clippings, coffee grounds from your local Starbuck's, sheets of newsprint, or shredded paper. Some gardeners drive around and pick up bags of autumn leaves stacked at the curb, then run them through a leaf-shredder or simply mow over them. In some places, tree-care companies and utility companies who trim trees near their overhead lines will deliver wood chips at no cost. Your town may collect and shred fall leaves, yard waste, and Christmas trees and offer free mulch to local residents. Be aware, however, that free mulch may contain poison ivy (wear gloves); I believe grass clippings don't pose any significant secondhand herbicide danger (I can't remember what I read a few years ago; I think there was an agricultural chemical that remained in grazing animals' manure, contaminating and damaging the vegetables that had been fertilized).

Garden clubs in your area may have fall plant sales that would help you.

English ivy is considered an invasive in many parts of the country, though apparently not in Ohio.

Since I can't see your photo, I don't know if this is good advice or not, but you may want to start small rather than try to deal with the entire area at once. I find that when I take on too large a project, the result is apt to be less than successful (of course that hasn't stopped me from trying to do too much).

Thank you so much for the ideas. This is very appreciated. So many wonderful ideas for not spending tons of money on mulch!!

Pam's comment about ivy has removed it from my book! will look to see if I can get some of the flowers you recommended. I know I can transplant some lilies that need to be thinned in my neighbor's yard (with his permission!). I love the idea of starting ornamental grasses from seed, thanks for think (I didn't know that it is common to do so)

I wonder what kinds of plants I can establish at the end of the summer?

Here is a link that might be useful: The weedy area (again)

There are a number of perennials you can establish at the end of the season & sometimes you can get them on a good sale at the nursery (fi they don't want to put the pots into a bed for the winter). Another option is to plan to collect seedheads from plants you like & prep the ground for them. Test the soil & add compost or other amendments as needed, then sprinkle those seeds on the ground & rake them in (barely). You might only get 5-10% germination in the spring (as opposed to babying them in flats) but if the seedheads are free ... why not try it?

Okay, I can see it now -- but I didn't get there directly, so I'll point out what I did that eventually let me see the photo. This has happened to me before.

Google/Picasa asks me to sign up for an account; I tell them no. I don't remember exactly where that takes me, but Google wants me to log in to my gmail account. At that point, I right-click on the Back button to open the drop-down menu of previous pages, and left-click on this thread to return here. Then I click on lukener's Picasa link again and there's the photo of the hill!

===

Well, of all the things I thought I might see in that photo, I definitely wasn't expecting that wall! What's growing down it?

How much water comes out of the weep holes (the round pipes in the wall) in a good rain? Is the area nice and damp after a rain, or does the water run off? What's the soil like?

Is that a small concrete path (or perhaps a bit of old foundation) between the grass and the weedy area?

[Yes, I know this is probably more work than you're interested in, but ... particularly if the soil's thin, stony, or otherwise not good, I'd be tempted to add something -- edging or a few inches of recycled concrete slabs, extra cinder blocks, or chunks of rock -- along the concrete to make the area into a raised bed. It wouldn't be a very deep raised bed: just level with the base of the existing Big Gray Wall. Fill up the bed with whatever you can find: leaves, grass clippings, dirt if you have any extra, cardboard -- anything you'd put in a compost pile (including kitchen waste). Add earthworms occasionally when you come across them in other parts of the garden.]

Something to add about free wood chips: even if a tree service won't give them to you for free (they're delivering them to you, after all) the price may still be a bargain. If you're not in a hurry, they might be willing to drop some off for a lower price the next time they're in your neighborhood.

Also, you could ask your county's Cooperative Extension office for garden club sale info, or sources of free or low-cost mulch or even manure.
http://extension.osu.edu/locate-an-office