That's a decent price for 2 new. Used it's pretty much on par. For $100, you'll be loud. Double that and you start getting into a completely different category, but for $100, you're going to do quite well. Get a decent 300w amp and build (or get built) a good box [makes the difference] and you'll be set.
Any respectable 300w amp you can get your hands on for a good price. Not a market I browse in, so I wouldn't be of service to you other than to tell you to find a Kicker 200.2, 300.2, 300.1 or 400.1(a bit much) at a good price. I'm sure there are hundreds of amps good in that power class, however.
rockford p3001 1st gen is the best 300 rms amp for this sub, recently had 2 of these in ported box, this sub are very good for the money and very efficient