Rocky Mountain Bus Sales in Monument, CO usually has a nice selection of used buses. However they are very proud of what they have for sale and the prices reflect that pride. They are able to get the higher prices because CO spe'c buses usually have big HP, big transmissions, and auxiliary braking systems.
Search Used Bus Inventory - Used Bus Sales - Used bus for sale
Masters Transportation purchased Mile High Bus Sales so they are the other big dealer in CO now. Since they are a large company with locations in at least five states now they do have some inventory. As to where it is located I have no idea. After a quick look through their online inventory it would appear as if they scrapped any junk buses and what they have for sale looks to be in pretty good shape.
Canyon State Bus Sales in Glendale, AZ is the Blue Bird dealer for AZ. They usually have a good selection of used buses. Some are pretty used up as unpaved roads in the desert can really beat a bus up over time. But some are from urban/suburban districts that have spent their life in a dry climate with no road salt. As a consequence the prices can tend to be a bit higher than back east but minimum spe'c for HP and transmissions are a lot higher than back east as well.
Tillery Chevrolet/GMC/Blue Bird Bus in Moriarty, NM is the Blue Bird dealer for NM. They do not usually carry much in the way of used inventory. But if you tell them what you want or need they can tell you what they will be taking in on trade in the coming weeks. Their prices are very reasonable.
2000 I/c School Bus for sale in Moriarty - 1HVBJADR3YA927885 - Tillery Chevrolet GMC
Auto Safety House is the Thomas Dealer in AZ. They have several locations and I don't know for sure where their used inventory is stored. They usually have a nice selection even though it rarely is very large. Prices are usually very reasonable.
RWC Group is the IC Dealer in AZ. They generally have a few used buses in their inventory with reasonable pricing.
Current Inventory - RWC Group
Lewis Bus Group is the Thomas Dealer in UT, CO, ID, MT, NV, and WY. Considering how large they are they keep very little in their used inventory. A lot of their used inventory they sell to Rocky Mountain Bus.
In Stock | Lewis Bus Group
Hartley's School Buses in Rugby, ND is the Blue Bird dealer for ND. They also operate school bus contracts and do charter work. Some of the better used trade ins go into their contract fleet. They normally have a handful of used buses for sale. But like many of the other dealers, they can tell you if and when a bus you might want or need will be coming in on trade.
Hartley's School Buses, Inc.
Of course Harlows has a presence east of the Rockies since their headquarters are in Bismarck, ND.
Navistar International truck dealers are sometimes IC Bus dealers like Brattain International in OR and RWC in AZ. But a lot of them like Woodpecker Truck in OR and RWC in WA are not. In other words, sometimes you may find a used bus on a Navistar International truck lot. Most of the time the bus business is the ugly step child and most of the truck salesman have no idea what they have even if it was three feet in front of their face.
I hope this helps.