I have been successful rooting roses from bouquets in the past, but for some reason, I never thought of doing this with the $2 roses I bought until a couple of days ago. The roses themselves were past their prime, so I'm not sure if they will successfully root or not. I really have nothing to lose except for some soil, a little rooting hormone and time.
Dip the bottom in root hormone then put this stem in potting soil. There are two ways to do that - first is to put just a small amount of soil in the bottom, put the stem in and fill in around it or you can put the soil in first, poke a hole with a chopstick or dowel and put the stem in being careful not to brush the hormone off when inserting the stem. Some people say not to use soil, but instead use soaked perlite, then fill the container with water. Others say to just use water to root the plant in. I didn't have perlite on hand, so I opted the soil method.