Scenario 1:
You have practically zero income and need a bicycle.
In that case, it's worth going over dozen bicycles, trying to make one decent, working one out of them - picking parts, mix-matching.
Scenario 2:
You have practically zero income and no other means of getting it.
In that case, it's also worth making at least a few bikes that work and can be sold out of all the trashed ones.
Scenario 3:
You actually are earning some money.
In that case, you can do it as a hobby / extra work.
But for it to be more "financially reasonable", it boils down to estimated income of re-selling the bikes, minus the cost in parts to make them work (if some parts are bought, either new or 2nd hand), then divide that with the number of estimated man-hours to haul all the bikes, fix them and sell them. If the number is higher than your current hourly rate - go for it, if you like.
All this if you have means to get the bikes delivered and stored without any extra costs. If that costs as well, it needs to be considered.
It might be worth looking over the bikes, before making any decisions - if it's possible to take a look. See what you're dealing with. If that's not possible - well, it's a "cat in a bag" as they say here. Rarely a profitable deal.