Welcome to iRV2.
If this is the engine mounted dash air conditioning compressor , then I'd check out Freightliner ( assuming your chassis is F/L ) when I needed the compressor 3 years ago F/L had the best price.
If your chassis is Freightliner , give their free help line a call ; with your serial number; and ask for the compressor part number . With that number you can do an online search for pricing.
99DSDP 3884, Freightliner, XC, CAT 3126B, 300 HP /ALLISON 3060
2000 Caravan toad, Remco & Blue Ox.