Use old bathtubs, stock tanks, a series of very large pots, or pre-formed pond liners, or build your own lined box pond.
This old bathtub just needed a bit of cleaning and painting. Fill with water and add a small filtered pump, a few small goldfish, and some plants. Put it in an area where you can see and hear it, maybe near your front entrance or near a patio with access to an outside electrical outlet. Do a bit of landscaping around it, either in the ground or in a group of pots, and you will have a lovely water garden.
This small feature took practically no digging at all. Just take advantage of what nature has given you. My yard has a small slope and dip in the grading that was very easy to take advantage of. Just a few shovels full of dirt was all that was needed to make a nice level spot to set a small pre-formed pond. Add a bit of sand, some bricks and rocks, a pretty pot, and an interesting fountain pump. This pond has attracted a few frogs to visit and is filled with tadpoles. I also put several large pots of marginal pond plants nearby to add height and interest. At some time in the future I may want to move this pond or do something a bit different with this area. All I will need is a wheel barrow to cart away the bricks and rocks. Then I'll empty the pre-formed pond and move it to a new location.
Build a Box Pond
My box pond is approx 4 1/2 feet by 3 1/2 feet and 2 feet deep. It has 4 x 4's in the corners and a plywood bottom. The sides and the top edge are 2 x 8's and we used a scrap piece of rubber roofing to line the box. This is well constructed and a bit heavy to move, but it can be moved with the help of a couple of strong friends. We originally had this sitting on a brick patio and moved it several years ago to a new location next to the deck.
Thanks to all for your support and encouragement.