It depends on the division -- program prestige means far, far less at D2 and D3 than it does at D1. It also depends how much effort the Sim invested in the player -- use Future Stars and see what Word on the Street says. If the kid is "tight" or "definitely leaning" you're going to have to spend some cash. If he's "keeping his options open" or is "prone to other offers" or any of the other barely-considering messages from WOTS, then you might get away as cheap as a phone call, a campus (or home) visit, a scouting trip or two and the scholarship offer and already find yourself in the lead. Much like pull-downs, there is no magic number that assures success. One last note, unless you're worried about someone seeing you in a battle with Sim and going after a different recruit, there's never a need to "knock him off" when it comes to a Sim. Once you get into the lead, you're good, unless it's late in the signing period. Sims only invest effort twice in recruiting, once before humans can even start and a second push with roughly 24 hours remaining 'til signings close.