Mike I buy these in bulk when they are an sale for under $7....and I use them as disposables for clear and colored dope
I used to try and keep the tubes and spray nozzels clean but too much grief...

The Nozzels are NOT good for fine detail and you must thin 50% or More in my experience to prevent sputter

I much prefer these to the 1" sable hair brush for doping large areas....just faster for me

Bottom line I like them for projects that setting up the HF compressor, line, filter, detail gun...is sort of a PITA --and then I am obligated to clean the gun...preval sprayer with 1 oz left over...in the trash...done!

https://www.ryderfleetproducts.com/preval-sprayer-pve267/sprayer-paint-complete-unit-p-tol-pve267

I have bought dozens of these under $7 for several years now

Last order
6 each @ 4.69
shipping 7.95
Tax 2.32
total 38.41

net was $6.4 each

http://www.restockit.com/preval-sprayer-paint-sprayer-num-pve267.html

A little cheaper, but out of stock and who knows of the shipping?!

At McFadden Dale hardware I found some 2 oz bottles that screw right onto the Preval power unit. Much better size for most of my work! I just cut the pickup tube to fit.