My friend and I are looking into building a simple, cheap slider. Anyone have any plans for a simple movable slider and how much we can expect to spend, thanks

My friends and I used to build sliders on Carlsbad Lagoon. They were cheap and easy to build and very movable because they were illegal...so it should be just what you're looking for. The entire thing is built out of 2x4s with PVC pipe on the top. Coming down from the main beam were two or three (depending on how long the rail was) supports about 5' high. they were braced to the main beam, and also at the bottom to 2x4s on the ground. Our rails were usually small enough that we could transport it in the boat...I think the longest one we made was around 23'. Find a shallow spot on the lake that has a hard, sandy bottom. Then anchor the rail with buckets filled with bricks, submerged under water, hanging from the supports. We had to repair the rails often because of the cheap construction, but it's the only thing we had to work with. After the session was done, two guys could pick the slider up and stash it in the bushes, away from the cop's eyes. Oh yeah, it cost nothing to build because we got all our materials from the scrap piles of local construction sites.