Can I put any paint down as a first cost on my deck before decking paint?

=== 1st coat is best with oilbase enamel --- is your expensive deck paint an oil based paint ... read the label on the Kilz to see the properties of that base coat ... call the paint center at Lowe's and see what they recommend for your area ....

Very poor idea. If the first coat doesn't adhere properly, neither will subsequent coats. Your expensive deck paint will peel right off along with the cheaper stuff it's resting on. Why buy an expensive paint and then go cheap on the primer? Proper surface preparation is the key to any paint job and if you do it right it can take longer than the painting itself does. Get that wrong and you can cause yourself a lot of extra work fixing it later. Especially on a deck, which gets walked on, only use products designed for the purpose you're using them for.

First, clean your decking well before you put any paint down. Be sure to clean off any lose, old paint that may be flaking too. Then, you can use a primer coat of paint but, the primer coat that you use has to be compatable with the new paint that you bought. I would talk to the people you got your paint from. By the way, for a deck, you probably want a semi-gloss, oil-based paint. That would be much more durable than a water-based paint. Although, it will be much more expensive.

karen is right. however, killz is a good primer and should work very well. the only issue would be the color of the other paint. it may not cover in one coat. the only other thing i would look into is if your deck paint is actually paint or is it a solid sain? if it is a solid stain then it needs to penetrate the wood. if thats the case a primer would make the stain not adhere.

difficult factor look on using yahoo or google that will can help