Add the bot to your server using this link.
It's a really simple bot, which uses mostly self-explanatory slash-commands.
/pb once — rolls 4d6, dropping the lowest die, 6 times, and sums up their point buy costs.
/pb once 6 24 40 — rolls 4d6d1 6 times, rerolling until the point buy cost is at least 24 and at most 40.
Another option is to repeat rolls with the following syntax:
/pb repeat number_of_repeats number_of_abilities min_accepted_cost max_accepted_cost
E.g. /pb repeat 3 would roll for standard six abilities three times.
The costs need some extrapolation, since the usual Point Buy system only allows values from 8 to 15, so this bot uses custom rules from this popular Point Buy calculator.