Buy a new pair. There are other spots on the waders that have worn down too but may not be noticeable. Like @jifigz said it will probably cost the same if not more to pay someone else to repair them in terms of labor cost. I don't even think anyone does wader repairs commercially as it wouldn't be profitable. So yeah, buy a new set.
I buy waders annually, and no, this isn't to toot my horn. Mathematically, even if I wore my waders for the entirety of the year (which I don't) (I used waders for about half the year) it would cost me (at most) $17 a month to be water proof. That's a meal out in town for most.
My mentality for this hobby and how I spend my money is determined by two things, indefinite tools (rods, reels etc.) and wear items such as waders and lines. I'll go crazy on the gear that doesn't necessarily wear down and can last my lifetime. Waders and lines, not so much, though I'll spend good money on fly line if one of my rods really likes it. No offense to anyone who implements the use of expensive waders and lines. It would be fun to have a crazy expensive set of waders to "flex", however I am far too clumsy and hard on my waders to entertain this notion. I don't care how good someone's waders are, they will leak at some point. Ultimately it's your money, spend it as you see fit.
