Cheapest way to wire a long distance valve?

I finally got my system wired up to a controller. 7 of my valves are on one side of the house and 3 more are on the opposite side. I mounted my controller direcly above the 7 on the side of the house. I only really need to power two of the other 3 valves. I did some quick measuring and it's about 80feet distance and I'd have to run at least 3 wires. I went and priced out 250 feet of 20ga wire and Are there any alternatives out there?

Can't think of any at this point. If this was an installation in progress, I'd suggest the valves be in one location and run more pipe, but I doubt if that would be cheaper than 250 feet or so of wire, just makes more sense to me to have the valves in one location, and it would avoid running wires any distance underground. But, you gotta deal with what you have, not what you woulda coulda had and I see not alternative to the 3 wires.

Yes this system was installed years ago by the previous owner. I surely would have done it differently. I should include that I will not be burying this wire I'm going to run it underneath the house. It's basically a straight line across between the two sets of valves and there is a vent right beside both of them to run the wire out of.

What you may want to try, it's a bit cheaper, is if you can get ahold of some Cat5 communications cable. Make sure it's Non-Plenum or PVC as it's called by some. It's got 4 pairs in it at 24 gauge. I've taken each pair and twisted each individual wire from each pair together to make up the difference in size. I haven't had a problem with it working at all.

It's funny you mention that. I have buddy that does communication work and he said he had a few rolls of that laying around. He's gonna give me a couple hundred feet to do the job.

You could also use a DIG timer. They don't use any wires.