I also am on a limited budget. This means that price is also a consideration. Sometimes an older model will have a very similar set of features to a newer model, but be cheaper because it is older, or even a used one might show up on eBay at and exceedingly low price. So I'm trying to find to find the best features for the lowest price, even if that means buying a 5 year old DSLR.
The lossy compression will make a tiny difference. More important things are going to include the condition of the camera, the quality and condition of the lenses, the settings for the image, your skill, and any post-processing you decide to do. The compression isn't like a badly compressed JPG where you can see the artifacts in it. Also, if you zoom way in (known as pixel peeping) on any image from any of those cameras, you'll see slight blurring, because of the anti-alias filter - only a few newer models don't have that filter.
In short, I wouldn't even worry about lossy compression. There are so many other things that can go wrong in a picture that compression isn't even on my list.
Personally, if I were sticking with the Dxx series, I'd go with a D90. But I think you can pick up a refurb D7000 for under $500 now, and the older D3xxx and D5xxx series cameras are probably even cheaper.
