I love our hardware and it was not expensive (vintage on ebay). You can also pay crazy amounts. It depends on the sizes, finish, brands, etc....
I'd figure out how many of each you will need and then figure out a ballpark for each and only search as high as you have budgeted. You can fall in love with less expensive ones or prohibitive ones. I would suggest looking for deals, online coupons, rebate portals (like shopathome.com) and looking at places you may not have thought of, such as ebay or Ikea.
Prices vary a lot as do styles, so nothing beats doing your homework.

Thank you for the link! (:

We bought 22 knobs and 22 pulls for a total of $117. We weren't looking at price tags as we were looking, just finding ones we liked. Lucky us, we seemed to like the ones that weren't so expensive. The store is also really competitive on that line of hardware. On the other hand, a year or so ago, I bought 4 knobs and 1 pull from the same hardware store for a toy box I made. I seem to recall that the bill on that was around $40. It's a cool toy box, but nothing about it was inexpensive.

I just bought knobs and pulls for kitchen, two baths, hallways, etc. On-line was cheaper than Home Despot or Lowe's. Ended up also getting a bunch from Restoration Hardware. If I had had more time I would have picked ones I liked from there and then found them elsewhere. Overall, some of them were less than a dollar each and some of them were more than $10.

We needed 48 pulls (mostly) and knobs for our kitchen and it came out to approx $175 all told, but we have extras and that also included 4 pulls and a knob for the bathroom vanity. I bought from several ebay sellers and was lucky to find matching vintage pieces (our back side of our island has a slightly different style, but no one will ever pick up on that). It took some waiting to get enough, but I started early.
My only regret is I should have gone for all pulls and skipped the knobs. I like the knobs, but I like the pulls even more. If I ever have extra cash (lol, with everything else that needs doing), I may switch out the knobs for more pulls.
Hope being more specific helps.

We bought 38 pulls of varying lengths (mostly 5" and a few shorter/longer) very heavy nice ones. Amerock, I think, online for less than $100. I was expecting to pay more but was pleasantly surprised that we liked a very inexpensive option! The ones longer than about 7" get astronomically expensive, like $40-$200 for "fridge pulls" and such. Hence, 2 5" pulls on our 30" drawers rather than one 12" one!

Its really hard to say. If you ask some people, I have expensive taste, my knobs were $6, my pulls were $8. I thought that was expensive, however, combining looks and feel, that was where we ended up. Online I found ones for $2-$3 that looked good, but didn't feel as nice in person.

my cabinet maker says we got away cheap, normally his clients are buying more expensive stuff.

All told we had a lot of hardware, it was close to $350.

I just purchased mine in the last month, and ended up buying off of Amazon! I only paid 99 cents for the knobs and maybe like $3.50 for the cup pulls...can't remember now, and free shipping too! I got ORB, and went pretty simple, but super happy with what we got. They are nice, the knobs are not hallow in the back, they are solid.

I purchased Hickory Hardware's Greenwich pulls in their stainless steel finish from a local decorative hardware showroom. I have 51 pulls ranging in length from 7'' to 19'' with most of them being 10'' in length. My order total including 5.6% sales tax was $470.65. It was very hard to find contemporary style pulls that had a variety of lengths and were not the type that catch your clothes when you get to close to them.

Here is how I budgeted for them. Counted how many I needed. Went to the Restoration Hardware website and had a look at their pulls. If I liked one or two of the styles, I would have budgeted $20 each. Lucky for me none of their pulls worked with the style we were going for. After that, we budgeted $10 each. Found the one we wanted at Lee Valley for $6 or so.

Get a few extra to have on hand just in case.