Without this soundling like a rant --- Boas and Balls carry different bacterias which are benficial to them, but not to the other species, prolong exposure to these bacterias can cause the other species to get sick. Also if you have two males, when they reach sexual maturity they could become aggressive to one another, if you have a male and female, you may have other issues you'll have to deal with at sexual maturity. At the very least you need to take into consideration that cannabalism in snakes, tho rare in balls and boas does occur. Its not worth taking the chance. And please don't take this the wrong way but if you cannot afford to properly house two snakes, why did you purchase two snakes? At the very least you can pick up a sterilite, heat pad, a hide and a water bowl for about $20 for your ball.
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Tosha 
8.15.0 Ball Python (Harry and Fluffy and currently un-named)
1.0.0 Angolan Python
0.2.0 Feline (Pippen and Pandora)
0.0.1 Dessert Tortoise (Pope)
2.2.1 Fish (1,2,3,4)
0.0.3 Lizards rescued from pool skimmer