The first thing you need to find out in selecting a mattress is how big you want it to be. Normally, people choose single beds if they're sleeping alone. Nevertheless, a double mattress wouldn't be so bad either. This one is the much better alternative if you're sharing the bed with somebody. Given that sizes are generally fixed, it's completely fine to buy a bed mattress online.
I believe a better technique for memory foam mattress topper evaluations is to merely explain the tested aspects that are acknowledged in the market as being what a great bed mattress topper is made from and then let you compare any topper you are thinking about versus that check list.