I know you can find BNIB MB Quart PCE 216 6.5" comps on Ebay for under $200 shipped. There's been people on here that have attested to giving their PCE's $150w RMS without any problems.
Don't worry so much about the rated power. Finda set that sounds good within your budget and go with them. Set the crossover correctly and you'll be fine. You will never run anything near max continuous power to a mid/high driver. The biggest concerns you will have is trying to run too much power at too low a freq and bottoming out the mid (set your crossover right and this isn't an issue) and clipping an underpowered amp tryingto get more output and cooking the tweeter. Having an amp larger than the rated power of the comps is a good way to prevent the latter.