Please put 1 10 in the proper airspace enclosure rather than being like everyone else around town who has two crappy subs in a ported prefab box... My single ten in a 1.25cuft box blows away a lot of two twelve setups... Its all about setting the system up correctly. Look into re audio subs on sonic electronix. I have used the 12" and 10" re audio sex series. They would be within your budget. Then you can get mb quart amp that will push clean power at a budget price.
2 Sundown X10's in 2.5cuft Net tuned to 31.65hz
SKAR SK-1500.1d, SKAR SK-85.4
Lots of Audio Technix 0 gauge
XS Power 1200,XS Power XP3000
I murder lowssss