We have a smallish house, so I wanted something compact (well, as small as a high chair can get). The FP Space Saver has been great. We also have a FP Healthy Start booster/portable chair that we really like. It just straps onto a regular kitchen chair. Not the most comfy, but if you plan to eat all your meals together with LO, its nice to have a chair at the table for them. Also great for road trips/visits to grandma's house.
I don't think either were terribly expensive.