If you buy from Ebay, then always buy in lots. Flesh Muscle are worth no more than $1 a piece. Although, Claw and SC can fetch a higher price. Claw because it's a very popular sculpt. And SC because it's an uncommon non-poster figure. I could see a Claw going for $5 at the most. Only if you really want one. And the highest for a SC would be around $25. These are just my opinions. I have def over payed when I was getting into collecting Muscle a couple of years ago. I was also buying single figures back then. You'll have a better chance at getting those two figures at the lower price by buying in lots.
You could also make a "Need Toys" post on here. People here might not have a Claw or SC for trade/sale, but Sunshine is more common. And with a few different sculpts! This is where you'll be able to buy single figures for what they're worth.
I'v been in the game of watching Ebay for Muscle for the last couple of years. It seems to me that sellers(in the hobby or not) know what they're selling. You'll see lots with Keshi mixed in with Muscle. But it's obvious. And most of the time the seller will put that in the description. You can always message the seller if you're not sure. Ask specifically about the material they're made of. It's either going to be a hard plastic(Muscle) or a softer rubbery feel.(Keshi)
That lot would be good for a new Muscle collector. But most collectors already have most if not all those figures. The only figures worth having for a seasoned Muscle collector would be the Claw and SC. And in my opinion, the price has already gone to high for those.