I've painted quite a bit with an airless. The best cost-value I have
ever seen was when I purchased a used Wagner sprayer, threw away the
gun and purchased a Graco gun. The wagner is just a pump, all the
work is done by the gun-so buy the best. Carefully study the nozzle
types of any brand and match the orfice to the type of paint. Always
use a cone filter or a bag filter on the paint just before spraying.
They are cheap, work well, take up just a minutes and collect the
darnest crap and can be cleaned and reused. Leave the filter on the end
of the suction pipe of the wagner, and always clean out the gun filter.
(it's located in the barrel of the handle). Practice on a flat wall and
be very careful spraying in a corner where the paint load builds up
VERY quickly. One last comment- Allow the first coat to dry overnight
at least, before recoating. Using latex, the paint forms a skin which
appears dry but a quick second coat dissolved that skin and then the
whold lot runs.
Lowes and if you're desperate, Homo Depo, usually have used sprayers on
hand although you may have to ask at the desk.