I spent many months renovating a commercial building. The highest estimate received for painting was almost 10x the lowest! The range of estimates for flooring, electrical, roofing, and other big jobs was also laughably wide. Surprisingly, the low or near-lowest bidder was often a very acceptable and competent choice.
On the flip side, if you don't want a contract job for whatever reason (your lifestyle, buyer seems difficult, timing), just 5x or 10x the price.
It's easier to grit your teeth when you feel like you're getting overpaid!