My wife bought me a bag from these people for Christmas. Thye are sold at my LHBS for like $30 or $35. While these are more expensive than most BIAB bags I wouldn't hesitate to buy one again. The quality is really top notch. It has heavy duty straps to support the weight of the grain with loops at the top to hang the bag or put a string through it to tighten it to the pot.
I beat the CRAP out of this bag. After I mash the bag goes into a colander on top of the brew pot and I twist as tight as I can to get all the wort out of the grains. After twisting the bag (with the grains really tight) I take a 2x4 and smash the grains to get every drop out that I can. The bag probably has 15 batches under its belt with no rips, tears or snags.
While there are cheaper options out there I would but this again in a heartbeat. I cant say enough about the quality.