Probably should have started your own thread for that question but not a problem.

It is not reasonable to try to tell others what a good market value is without 100% of the information and even then, I may be able to get more than you because of my reputation and re pore with customers. 

Also, everyone has their own skills set and we all do things differently. 

You also must consider your work requirements: do you have- insurance and what kind? Gen Liab, Prof Services- errors and omissions, workers comp, hired auto for job site (additional to standard auto insure), medical, etc.  Do you have a fund for updating your code books?  A fund for no work periods?  A fund for equipment replacement or buying specialty tools you don't already have?  Do you have advertising- business cards, phone book, website, etc?  Do you have a company/work vehicle that will need replacing and travel expenses?  Do you have all the PPE that you will need on various jobs- hard hat, vests, climbing gear, safety boots, glasses, etc.  Do you have ALL the certs you will need- the CWI is just the beginning? 

Every region of the country and job market (pipeline, shop QC, QA field or shop, powerplants, etc) are all different. 

Welder Qualifications: that will depend upon how many tests, what kind of tests, material, thickness, and much more.  Do you have a bender?  Do you have report forms?  Do you have the code they need to be qualified to? 

Basically, I have a base price of $500 for one test in all positions to D1.1.  But, there is much more involved in my tests than what many do. 

He Is In Control, Have a Great Day,  Brent

Along with the other advice shared here, I would verify the my current employer does not consider this as a conflict of interest. Military primes are sometimes picky.