I've bought from zipzoomfly.com, kingston.com, buy.com and others. I have never had a problem with anything in the past 4-5 years, matching stick for stick with same memory footprint and company. I usually just do a search on those sites, or slickdeals or fatwallet for the memory type one needs. pc5300 ddr3, 667hz, 1ghz, 1GB, 2GB, etc. I don't think you can go wrong with the lower priced sites. BTW, I buy almost everything at Amazon including TEA, but for memory they have never for me at least proven to be the cheapest for the same memory from the same manufacturer