I have these after Eric Cressey hyped them up in an article of his from way back - they really do their thing in terms of enhancing grip but honestly I have ditched them for now in favour of going back to just raw lifting with liquid chalk -
For true added bar thickness I go with my TylerGrips (I know, sound like an infomercial) but here you go - www.tylergrip.com - to see what I am talking about.
One caveat IMO is that they are awkward to use in terms of overhead lifting - such as shoulder presses, overhead squats, power cleans, etc. Other than that they are decent.
Lynxgrips shipped to Canada come under $30 or so from the official website IIRC. Prior to any "grip aids" I just stuck to chalk & those round jar opening pads you can get from your local Food Basics supermarket for like $3.00 a pair - they last a few months in the gym and those aren't bad either.
Try not to be the thick sponge guy @ the gym