Wow! What a wide open question! LOL
A lot depends on the amount of money you want to spend. Machines have quite a range of prices from less than $50.00 to over $10,000. and from the most basic straight stitch only, to one that will do most everything except cut out your project, and everything in between. I would suggest you go to the websites of the manufacturers like Singer, Brother, Janome, Bernina, Babylock etc. and see what the different machines can do. A google search of sewing machines will get you started. Once you decide on the features you must have, then find a store that carries those machines and do a test run. Take some of your denim with you so you will know it sews properly on that particular fabric.
I wish you luck and know that you will find the perfect machine for you.
Murphy
Here is a link to a site that gives lots of information on sewing machines that may be helpful to you.

Here is a link that might be useful: http://sewing.patternreview.com/

Sorry, didn't know that there was that much involved! LOL As you can probably tell my Mom is the sewer, I'm the decorator. But thank you so much for the link and all the info. You gave me alot to think about. I will jump onto the site you gave me and get my research going. Again, thank you so much!!

Jenn

Hey Jenn:
You didn't ask but I will tell you anyway how I know so much about the supposedly simple act of "purchase of a sewing machine". Did it myself a couple of years ago and could not believe what I learned!!! Simply could not believe the vast differences in something as "basic" as a sewing machine. Took me several weeks of research to choose the machine I wanted. I did end up with a Janome 6600 and absolutely love this machine. I also make purses along with quilts, clothes, home decor items etc. This machine does it all. I love it so much that I also bought the Janome Jem which is a smaller lighter and less expensive machine to take to classes etc.
I would also suggest you get as much machine as you can afford. This is a long term investment and a good machine will make your sewing much more enjoyable and easier.
Good luck
Murphy

take a look at the Singer 401A or a 500A. It has all metal gears and easily sews through 8 layers of commercial denim.

It is an old machine that is still a work horse

I prefer the 400 because you don't have to lift the lid to put the spools.

Here is a link that might be useful: Singer 401

Sorry westbrook, but I think 401s or 500s are really really bad choices for sewing heavy fabrics. While they are all metal, they are slant needle machines, which was only a sales gimmick of Singer's in the 1950s. The idea behind this sales design/promotion was that the slant created better visibility of the sewing area. But when sewing heavy or dense fabric, the slanted needle tends to deflect, resulting in lots of broken needles and scarred stitch plates.

Vertical needle machines have much better penetrating ability. If the OP wants to go vintage and cheap, I'd recommend a class 15 machine, either a Singer (15-91) or one of the many Japanese post-WWII copies. These should cost in the $20-$100 range, but are straight stitch only. Heavy duty zig-zag machines are harder to come by. I bought a used Singer 20U industrial for $500, which is likely tougher than any domestic machine, but it still isn't recommended for extremely heavy work.

I have a Bernina 930 and have no trouble with several layers of denim or anything else for that matter. I agree....decide how you will use the machine and purchase the best you can afford. That does not mean that it has to be a new machine....look around and don't purchase on a whim...

If you sew a lot of denim, you may need an industrial machine. An *industrial* Juki, Mitzubishi, or Singer would likely hold up well. Do not buy an "industrial" machine on Ebay. They are just household machines that didn't sell well the first time around.

I used to be a fan of bernina, but truthfully, the last two I had could not deal with anything more than two layers of medium weight material. I had a 950, allegedly an industrial machine, that couldn't sew belt loops back onto waistbands. That's not a big task, or shouldn't be. And the one I still own, 153E, is fine for lightweight garment sewing, but the thread tention won't hold for multiple layers.