No idea. It is in part a precision device because of the gauge. Few that rent tools are careful with them. I look at it this way, it's an investment. I do drain/fills every 3-4 years and on multiple vehicles. The wasted gas isn't so much an issue as the assurance of no air pockets.

Time is the other factor. Once the system is drained and evacuated, you literally stick the hose into your bucket, open the valve and it sucks fluid in until full. Top off the radiator, top off the reservoir and you're done.

Vacuum filling is great and once you do that a few times you realize it's the only way to go. I personally have the mityvac mv4525 as it is a system pressure tester, t stat temp tester (works so/so), can give clues as to a blown head gasket with a running pressure test (building pressure with no or low heat increase), and also a vacuum filler. Another great thing about a vacuum filler is if doing any work on the car that required coolant parts being replaced then you can draw a vacuum and let it sit and verify it is sealed before dumping coolant and letting is run only to find it leaking and now lost 40.00 on coolant.

Mityvac

I don't remember the price but not bad for multiple all in one tool.