I have a little knowledge on this subject since all but two of the bikes I have built have been powder coated and have tried several different powder coaters and ended up going back to the first.
A lot goes into getting it done right.
1. Color and Type of powder.
- Basic RAL color are less expensive
- Exotic single stage colors can be expensive
- 2 stage or dormant colors are the most expensive
- Adding clear adds cost
2. Shop and Equipmnet
- Some have home made set-up and do it out of there garage - usually cheapest
- High grade digital industrial units - you pay for this technology
- Size of oven - cheap to heat up a small frame sized oven / expensive to heat up a 10x20 ft oven that is cost of energy
- Industrial vs Job Shop - It actually cost industrial shops more money to do small jobs because they have to interrupt larger production runs. They make money on volume and depending on nature of product quality does not have to be perfect
3. Who does the work and final quality
- I have found that industrial shops that do not typically do small project have poor quality - orange peel / too thick / too thin / do not know how properly mask /parts returned with blast media inside.
- job shop that tailor to cars and motorcycles have pride in workmanship and in my experience provide the best quality
- Lead times industrial shops can take months to do your work - they do it when they slow down job shops typically a week or so.
So as someone else mentioned you get what you pay for, I tried several different shops trying to find quality at a lower price and I ended up going back to the first guy I was recommend. The reason is the quality of work and finish, if he is not happy with the final product he will redo it at his cost. The biggest challenge with that is you do not know what it will turn out like until after it cures. Most shop will try and give you crap work and tell you that its normal.
5 lbs of powder is very high, most frames can be done with about 1lb it really depends on the equipment and nozzel size. $200 also seems high but I'm not sure what kind of shop you called. Shops willing to redo work until its right charge a little more in case they have to. I prefer that than to show up and be charged more because they had to redo it. It also creates an incentive for them to do it right the first time so they make some extra.
finally my thought on prep work:
Heavy gauge steel bike can be blasted but you have to be careful with the blast media and air pressure because they can be very hard on frames. Only frame I think this method works well on are worksman because they are so tough.
Thin wall steel frames should have original finish burned off and then a light blasting to prep the surface which takes off the burned finish.
Aluminum or 4130 Chromoly should be stripped in acid, washed and a very light blasting to prep the metal.
here are a few examples of finishes I have had done.
Single Stage - green was easy - yellow was tough was redone once - orange easy
Single stage with Clear - this one was redone once
2 stage dormant - This took a lot of work to get it done and most parts were done more than once.