Speed 05's are fairly cheap, very much underpriced and probably cheaper than a couple of pairs of fancy coloured goggle straps made in mexico.
Depends on whether 45/90 and condition. You should always investigate yourself on the classifieds and don't let your prices be dicated by anyone else. Chances are you get yourself a bargain and the seller will be losing a fair bit of cash. Just shop around and with Christmas coming a lot of ballers will have some realsim set in and be flogging their gear accordingly.