You must sell bikes in a different area than I do.

Cleaning is often worth $50 in my marketplace, a week or two of posting time at least.
I often replace chains but rarely replace cassettes.
7-speed cassette is only $10 more than 7-speed freewheel. 8-speed cassette's about the same.
I try to keep to the $10-15 tires for flips.
Never spend more than $5 on a saddle for a flip if you can help it. Many folks will swap out saddle.
Brake pads $30 tops.

A lot of items don't translate to more money that you can sell the bike for but if you don't have those items in somewhat decent condition then you might not be able to sell it at all. For instance wasted tires that don't hold air probably translates to -$60 but only cost you $20-25 to put some placeholder tires on. If you have a bike with enough wasted items on it you should probably consider stripping it down to frame/fork and parting it out.