Yeah the 95-98 Sportster or 96-97 Challenger single engine boats are about all you can find at that price, maybe a 95 Speedster. Unless you find something that needs work, your budget is going to limit you until the off-season.
Budget aside, the "best" boat is going to be the one that suits your needs and uses best. If you're taking 3-5+ people total regularly, a 14.5 foot boat is a poor choice. If speed, acceleration and towing power are very important, the single engine boats will disappoint. If lower fuel consumption is important the twin engine boats would likely be wrong for you.
I just bought a boat in this price range and decided on a 96-97 single engine Challenger. I wanted the rear facing spotter seat which the Sportster doesn't have (in these year models) and the 787 engine vs the 717 in the Sportster (110 hp vs 85.) They seem to run around $500-1000 more than a Sportster, but for what I will use it for, it was the perfect model.