i didnt pay full price for all of them, but most of them i did. but with a 20g tank, you dont need that many. the tank will cost you $20 and you only need a school of 10-25. so if you can get them, it should be well within your budget
20???? where are u from...lol more like 75 -80 without tax and i dont think it comes with a heater.. i will have ti use my 5-15 gal heater till i get more cash