I bought a couple of solar garden lights from Bunnings the other day. The "wood look" version (pictured below) is only $2, while the stainless steel tube version is $5. They are both intended for outdoor use (hence the solar bit!), but the "wood look" tube is made out of some composite material and I'm not sure how long they'd last outdoors. I bought these samples as they looked ideal for using as a low cost casing for LED lights and/or controllers. You couldn't buy an empty enclosure for $2 - $5. Anyway, the tube is 65mm diameter (O/D) x 180mm high. Even with the plastic spike and top cap installed, there is approx 140mm of usable height in the tube. The spike base has one ~7mm hole and a couple of ~3.5mm holes in it that wiring could be passed though. The solar cell, LED, battery and electronics are all mounted onto a black plastic disc that locks into the top cover. All items can be removed in seconds with a pair of wire cutters, leaving you with a consistent way to mount your new LED PCB or RGB pixel, etc.