I have dealt with PC Village (Yonge and Eg location) before and have had not problems with them and their prices are often very low.
When you go to the site make sure that Safari doesn't have pop-ups blocked b/c that's how you find out what their really bargain basement prices are for the week. Note that, like most computer/electronics discounters the prices are cash discounted (usually 2-3%) and that, if you want the really low prices from the web site you have to ask for them _explicitly_ when you go in b/c the prices at the counter are a few bucks higher than those on the web.
I notice that they don't have any PC133 SODIMMs listed on the web at the moment but they have a lot of stock on hand so I would expect to find it there.
I have also purchased from Logic Computer out in Mississauga (they have a bunch of other locations too) and they're pretty good as well but the restocking fee for returns is steep (I haven't bought memory from them so I don't know if there's a different policy for RAM). Note their site rots on Safari.