OBX exhaust is the best bang for your buck but will roughly triple your budget. However it does meet your requirements as an easily reversible bolt on.

I know other forum members have tried various cheap mufflers (generic Cherry Bombs, Magnaflow, etc. cans), but in general using one will require thinking, design, and welding which won't be as easily reversible and will blow your budget unless you can DIY it.

IMO you're not going to get a great solution in that price range. Spend a little more and get a bolt-on catback. If you (or the next owner of your car) don't like it you can take it right back off and sell it here.