This year I used 5 gallon buckets and mineral tubs used on a local cattle ranch. Make sure you drill holes in the bottom of your buckets - at least 6 - so the excess rain and water can seep out and not drown your plants.
I put 4 tomato plants in the larger tubs to save space. It's perfectly alright to plant more than one plant in each container. However, don't over plant.
Example: 5 gallon bucket can take 2 to a max of 3 tomato plants.
Over plant in your tubs. I sowed all of my carrot seeds in one of the larger tubs and was blessed with a ton of sweet baby carrots. Let nature take it's course as the stronger plants will survive, the others will rot and add mulch to your container soil.
*What are your favorite vegetables?
*What do you have around your home that can be used as a container?
*Container gardening also helps the environment and you are creating your own micro environment.