He drinks 15 bottles every month and there are 12 months in 1 year so that's 15*12 = <<15*12=180>>180 bottles
He earns $0.10 on every bottle that he recycles so that's .10*180 = $<<.10*180=18.00>>18.00
He has $18.00 and each bottle costs $3.00 so he can buy 18/3 = <<18/3=6>>6 bottles
#### 6