Hey guys, i have been considering getting vpn but don't know if i'll need it.  I plan to run 3-4 bot tabs with one account training or skilling and the other 2-3 running pretty low ban rate scripts.  My question is, will I be okay running 4 accounts on the same ip?  My IP is dynamic but doesn't automatically change, i have to contact my ISP.  So in the case of an IP ban I could change it, but will running 4 accounts on an IP be a giveaway?

You will be fine, the biggest thing is getting your ip flagged if you're caught. If you're just gold farming and don't mind losing any of the accounts then continue. If you're botting a main account then i'd suggest a vps, for your gold farmers. i run 4-6 accounts on the same ip, never bot my main on the same ip though. With a vps you're able to let your computer rest (by turning it off, since the bots will continue and it has a different ip/ Some VPS' have an ip change service, the one i used to use would cost $2 for a new ip. Good luck botting.

thanks for the info trippy.  once i get ip flagged is it too late to change my ip and continue, or do all accounts under that ip get banned?

Jagex does not blanket ban ip's. What they do is taint all the accounts which were using that ip, basically they watch them closely for botting. Even if you change ip's, these accounts will still be watched for botting (might be just for a certain time period), so they will ban them as soon as they see any evidence of botting behaviour. This only applies to goldfarming bans though(which is the only one which results in a tainted ip).