I have a suggestion. Unless you're going to be using the bike only on a dragstrip, i.e., in a straight line, the max. on shorter shocks you should go is 1-1/2" less than the 13" stock length. To maintain proper front to rear balance, whatever you take-off the front, the same amount in the rear.
That sets your maximum shorter length at 11-1/2" and anything shorter than that, you may run-out of cornering clearance, or if you take it off in the front, you may end-up hitting the radiator.
The least-expensive Progressive Suspension shocks are not rebuildable, and they are probably more-than your $200 limit. They are a decent shock, without the adjustability in damping of their $$$ and $$$$ shocks.
YSS Shocks are made in Thailand, and are an economical choice. You need to look online for their info on pricing.
https://yss.co.th and
http://www.yssusa.com/ They have a variety of models and prices.
YAMAHA 1985 - 2002 VMX 1200 VMAX L.30 VP031,2WE
,1FK,2EN,2LT ABE 1200 TS ABE 300-310 14x20 14x20 46-25-35-160
THREAD SPRING PRELOAD - - 10W