The problem is with some crafty types that sometimes they stick to their niche and don't really stray from that. There are stacks of crafty activities; knitting, sewing clothing, scrap-booking, card making, crochet, quilting, pottery, even glass-work. So I'll try to come up with ideas that will cross a wide variety, but even then, you may end up poking them into something they love with a gift a bit to the left of what they're already into.
Under $30:
One major problem that I find that comes with being crafty is that it is damn messy! and I never have enough space to put everything, looking into what sort of craft they do and finding a suitable storage solution to what they already do will be infinitely appreciated. Little plastic sets of drawers are great for papercrafts, while storage portable suitcases are good for sewing, Even tackle baskets are awesome for sewing bits and pieces.
Under $50:
Updating your friends stock of tools she uses is another good idea. as I often don't even realize that the needle I've had in my machine is about 5 projects old, and I didn't even realize that I shouldn't use the same pair of scissors to cut both fabric and paper for a long time. Buying them a new set of scissors, a new crochet hook set (and roll to keep them in!) can prove invaluable.
Another idea is to book them into lessons in a craft that they have mentioned in the past, but this is a tricky one, you need to have listened really carefully, and maybe even stalked their google history!
Under $100:
This present can seem a bit nana-ish, totally get that but so can half of crafty activities when you think about it, I still get called a babushka for my willingness to sew my nieces and nephews presents (FFS! it's cheap and chips and really personal, what's wrong with that??) So I'm going to suggest a Cuttlebug machine, or if they already have one, some stencils for it. It's worth hunting on the internet as they come in a wide variety of sizes, big shot are sturdy and can cut more materials, Cuttlebugs are your go to user friendly machine, there are other ones and if you're really confused, find yourself a shop assistant or online forum to see what other people think.
Cuttlebug 2