By the time he buys batteries and a charger, it's up to around $57, which is a big chunk out of the $80 he wants to spend. And if he ends up not liking the 5V, he doesn't have a lot left to get an alternative. He may love 5V, but I think he'd be better served to confirm that by exploring inexpensive options such as an $8 atomizer or a $15 dollar passthrough before dumping the larger part of his budget into a mod that he may or may not like. If he likes it after trying the $8 atomizer, he's still got plenty of money left to get a 5V box mod. If he doesn't like it, he's only out $8 and he's still got enough money left to get a 3.7 box mod.
Actually the batteries are a big advantage over the regular 3.7 volt batteries because they cost about $3.50 each instead of the $12-$15 for regular small batteries. Plus, they can be recharged about 2000 times before needing replaced whereas the small tube batteries have a 200 recharge life span. In the long run, a good mod will save you money. Plus you can get the batteries anywhere, not just from China like the small tube batteries. And from what others have stated on here, neither a pass through or LR atomizers, really replicate the performance of a good 5 volt mod. I haven't tried the LR attys but I have tried several pass-throughs and as others have reported, it's not the same.