I have a Howse sub-soiler, middle buster, trailer hitch combo. It was under $175. I only would recommend the modular units that allow you to easily switch from a sub soiler to a middle buster.
The Sub-Soiler blade get down deeper than the middle buster blade by several more inches. Mine used 2 bolts to swap out the blades/tralier hitch, I took out the bolts and inserted "top link pins" so now I can change the implement blades without any tools.
What type of water pipe are you going to bury and how deep do you need to go? Some types of pipe can simply be pulled into the ground by attaching a hook to the back of your subsoiler (drill a hole in the trailing edge, attach a cable or similar, then attach the other end to the pipe (with a screwed on end piece) and simply pull the pipe into the ground. You will only get about 10" to 12" deep with this method, but it is an easy way to get it under ground. Depending on your soil, you may need to make a pass with the subsoiler alone, then come back and follow the same path to pull the pipe. It is much easier than any other way I know, but only is good if you can live with a shallow burial for your pipe.
Similarly you can easly bury wire/cable/irrigation tubing using the sub-soiler. Simply attach a 90 degree elbow pipe (again drill a couple holes in the trailing edge of the subsoiler, use muffler clamps or similar to attach the elbow to the back side of the blade, run the wire/cable through the pipe from the top and out the back, tie it off at your starting point and drive slowly while feeding wire/cable/irrigation tubing, etc down the pipe).
I also used the sub-soiler/middle buster frame to make other implements. My pallet forks are the most often used implement I hang off of the same frame. I have designed a turf cutter, but have not built it yet.