I know this topic has been covered before, but I think it bears mentioning again. Please do not tip or pay souvenir vendors in Canadian or American coins. That includes quarters, loonies and toonies.
While at a beach bar last night, we were approached by an exhausted beach vendor who, when he found out I was Canadian, begged me to change his coins into pesos ... almost $20 worth. He had more coins, but I didn't have the pesos to exchange for him.
There's only one bank in Puerto Vallarta which will change these coins, and he must spend about $4 for the bus plus a bad exchange rate to do so. Consequently, he makes a real pittance on each sale. Sales are hard enough to get these days, so please remember to pay in pesos. Enjoy your souvenirs, knowing that the vendor can buy some tortillas and beans for his/her kids.