I know you mentioned that the Topeak was out of your price range but IMHO, that's really the upper-end of beam rack quality. I have one and it works great for around 15 lbs. of cargo but I would definately not go much above that and I would definately not use it for anything other than picnic runs on smooth roads or bike paths. Also, you'll want to keep your bulk down and panniers are definately out. Do you have a full-suspension or a hardtail? If it's a hardtail then I'd recommend a full rack.