I too was looking for a lower cost horizontal 3-4 years ago. I bought a Charbroil and ended up selling it in less than a year. It was junk even with mods. I then bought a Char-Griller Smokin Pro, made the suggested mod and it performed like a champ. I don't use it much these days since I built a much larger trailer offset. Here is the link to Char-Griller.
http://www.chargriller.com/