I use Safety First swing tray booster seats for all ages until they can sit on a stool at the kids' table. If you have any Zellers stores in your area that haven't yet shut down, they had some yellow and green ones with Winnie the Pooh theme that are only $19.00! The theme stickers are optional. I love these because the backs fold down, the tray closes over it, then they stack neatly. I've used them forever and have only had to replace a couple of my old ones now after 11 yrs. I don't even bother with the straps....they're on the floor anyway. Like you, I find highchairs take too much space.