What should I use are there alternatives to ones bought in stores such as future?

What is it that you want this extender to do? Future is a floor wax for creating a glossy surface and is usually used as preparation for washes (since the wash color floats into the cracks and crevices of a model). If you want an alternative to Future you can use Acrylic Gloss Varnish or Acrylic Gloss Medium.

If you are looking to make either acrylics transparent (as in a glaze) or to slow drying time then you can use acrylic retarder of which there are many. Golden Acrylic Retarder is very good for this and dries flat. Grumbacher makes SlowBlend and ClearBlend which are also very good for this and also dry flat.

I went to the chain craft store "Micheals" in the section with acrylic craft paints. The one I picked up is from American Tradition and, while it wasn't a cure-all for my clogging problem, it certainly helped. Maybe I need to use more?>>>anyone with experience care to share how much you use?
btw....I'm using an aztek dbl action, polly scale paint