it depends on how many watts the subs can handle. be sure to check before buying an amp
your average pair of 12 inch kickers would be well matched with a 1500 watt amp
it also depends on how they are wired. assuming, they are wired sererately, you would want to get a 2 channel amp to split the power to the 2 subs
a kicker zx 1500 would be a good one, but its like 600 bucks
a rockford fosgate 1500 would run you about 700 bucks, but these are the best brands in my opinion
there are lots of good brands that will give you a good amp for 2-4 hundred bucks, just be careful of ones you havent heard of and do some research so you dont fry anything