If you dont want to spen much money you will have to build a DIY system. You could try and get a second hand tank, make a DIY harris pole, and if you are in a hardwater area get a cheap RO.
You might be better to find someone who lives near you who would be willing to let you have a go with there system, im sure someone on here would be willing to show you the ropes, where do you live.]
I have not long chaged to WFP, and i was undecided as to wether i should change over, but now ive done it, i wish i had dont it years ago, it is quicker, but it is so much better than going up ladders,