Watering it down will not only cut it's opacity (thus requiring additional coats which defeats the purpose) but it also reduces it's ability to stick. If you absolutely cannot hold off on the project until you can afford a whole quart of paint, then a better solution might be to only paint the table top (and it's edges). Know, however, that if the table has not been painted before, then you MUST use primer first (I like Glidden's "Gripper".)

Also, for durability, choose paint in either eggshell or semi-gloss; flat paint will show every scuff and stain while not being scrubbable. I realize it's not in your budget, but finishing with 2 coats of water-based varnish (like Varathane Diamond) will ensure it's longevity.

Sure it will work, it will thin the paint. This will also have an effect on the opacity (covering power) of it, so basically what you're doing is diluting some juice and expecting it to taste the same. I would buy enough paint for the job, rather that doing it this way and finding out it's no good, then having to buy another 2 lots of paint to do it properly.

Best not to as the color and coverage will be poor.

Buy a cheaper brand - but more of it.

I need to paint my coffee table but the problem is that I'm on a budget and the pint sized wall paint's are a bit expensive. I know acrylic works on wood but I would probably need to add water to the acrylic in order to have enough paint to cover the entire table. So, if I add water to the acrylic, will it still work?

Thanks