I believe I got a much smaller bag from lowe's, there isn't a home depot close so I can't say.

I found it both at Lowes and Home Depot, and smaller local nurseries. Go easy on it, over fertilize with RoseTone can kill a rose.

I get mine at the local farmer's supply.

In Wyoming? Probably nowhere locally, sorry. According to the Espoma site, there are vendors in Texas and Oklahoma City. The big box stores are not always consistent on what they carry. You might want to check out Espoma Rose Tone, print out the spec sheet, and then go to some local garden centers to see if they have any products that are close in composition.

There is also Mills Magic Mix, but that might prove to be even more cost prihibitive for you.