As a keen watcher of Gauge 3, just to see what they come up with next, I have to put in a plaudit here for GRS, who, IMO, have almost single-handedly brought G3 way down the ££££££££ list from what it used to be, to more like just the £££££ list. Even so, the Thomas trucks can, with a little work, be made into pretty good replicas of the average British two-axle wagon.
Locomotives for Gauge 3 will ALWAYS be expensive, a matter of the size of the market and the physical size of the model. Live steam UK-outline locos are always going to be north of a thousand pounds, even as kits. But they sure are good looking, right?