Is he 100% on Liquid force? i mean if youre not gonna get him an flx maybe try other brands.
anywho, dealadaywake is an awesome site for finding steals, right now there are some slingshot options for 80bucks. and you could pick up a ss board for 300. When i was searching in your price range I found a hyperlite process for 200 dollars that i absolutely love and has done great at the park and behind the boat.
Also, if you know of a store nearby that sells boards, you can ask somebody, maybe like the board areas superviser if they have any deals, I went to an overtons and they tried to sell me a LF tex for 225. should have let them.