When it comes to body work there are two important things to remember.
1. If it's cheap, it may not be good
2. If it's good, it will not be cheap
Take a moment to think of (or go out and price) the cost of materials now.
And this is for quality materials, ie PPG,3m ect
1 roll 3/4 in masking tape- $2.75
5 gals cheap thinner for clean up of spray guns
Masking paper, 18 in wide roll- $41
Sandpaper, wet 12 sheets 600 - $14
High quality body filler- $36 / gal
Polyester fill putty w/activator- $22 (1 tube)
Primer surfacer: $65-120 / gal
Base color- depending on brand and color tint
1 qt- $40-70 average
1 gal- 180+
Clear coat- about the same
To do a flame job on a vehicle you will burn through at least $100 worth of tape and mask minimum....
You can DIY...if you have all the tools and a suitable place to do it. If the shop you got your estimate from has it's own paint mixing system think of the money he invests in it each month to replace bases and tints.
Just trying to bring things to light for you, thats all.