I'm looking for a way to get negative levels removed on another cheaper than 1000gp or 8 levels of a certain monk archetype.
You can get a level 7 cleric.
Joke aside, there is no cheaper way of removing negative levels.
It costs a feat (Experimental Spellcaster) for a divine caster, bard, or alchemist.
Dragon's Blood. 180 gp needed, no more than once a week for that person... but it works. If you have a cooperative dragon you might even be able to make it a renewable resource! (Except hefty bribes to the dragon in exchange for the blood on top of lesser restorations to restore the stamina damage)
Black Soul Shard is a preventative measure rather than healing, but it might be worth considering. And while expensive it can also function up to once/week.
A Staff of Restoration would be expensive but worth considering, I think, especially if you anticipate having to remove many negative levels throughout the campaign. (Cheapest cost-to-create is (400*4*8 + 1000*50)/10 = 6,280 gp, but that'd require 10 charges every single time you'd want to use it so you'd probably want to make it more expensive in exchange for fewer charges/use)