Personally I dont think $34 is over expensive either for something pre made plug and play. You can get rid of your storage tank if you have a profiLux for under $80!
http://www.autotopoff.com/solenoid/
When you work out the cost of a storage tank - feed pump - pipework, i doubt the cost comes to much less, also take into account the fact you do not have the space issues and also only having to run 1/4" pipe. For me this method is a no brainer
