Carlton started off as an economy hotel when it was first built. I believe the prices of the rooms went up after a series of tourist spots sprung up in the vicinity - the casinos, Garden by the Bay, Helix Bridge, Esplanade etc. The entire hotel went through some major renovations and upgrade, and after that the prices have become more expensive than the hotels along Scotts Road except Goodwood Park.
I will opt for Rendezvous Hotel along the same stretch for a much lower price. But I understand the restaurant or cafe @ Carlton is pretty popular.
There are still a number of hotels in Orchard vicinity going for $150 - $200. It's getting below $150 that requires some research, and the ones nearer to the $100 mark is a challenge.