I'm a total cheapskate. The combination of that and a love for recycling and re-purposing has led to my obsession with finding container garden ideas that can be done on the cheap. Here are some of my favorites.
When my kids were little, we always had a lot of juice boxes lying around. Now I have to get them from the neighbors' kids. They make great containers, though they are small so will need lots of attention so they don't dry out.
You can even use juice boxes for starting seeds.
Cut holes in the bottom for drainage and then put a piece of plastic screening, coffee filter or paper towel over the hole. This keeps the soil in while letting water out.
Growing small herbs, or flowering annuals works well.
I love growing stuff in reusable grocery bags. They are cheap (usually $2.00 or less), and plants love them. I've grown giant tomato plants in the larger size and have grown everything from lettuce to herbs to flowering annuals in the small, lunch sized bags. Whole Foods has some great bags in both sizes.
You will want to get the kind that has plastic on the outside. It usually has some kind of fabric on the inside. I cut holes in the bottoms and line them with plastic screening. I also make slits about half an inch from the bottom. The reason you want to do this is that if your bag is sitting on a non-porous surface, water can have a difficult time getting out of the bottom holes. The slits on the sides will make sure your drainage is good.
My whole family loves Clementine oranges. We eat them by the boxful. In season, they cost anywhere from $5.99 - $8.99, which is not bad considering all the fruit and a free very cool container.
I line the Clementine boxes with newspaper to maximize the ammount of space for potting soil and also it helps retain some water. I fill them with pansies and violas in the spring.
I also line them with plastic and put small pot of houseplants in them during the winter.
I love planting in Crocs, especially baby Crocs. I find them at second hand stores and yard sales. You can also use any rubber or plastic shoes, though you'll have to cut or drill drainage holes in them.
Shoes don't have lots of room for potting soil, so you have to make the most of the soil you can squish in. It's also a good idea to choose plants, like succulents that are fairly drought tolerant, because the shoes tend to dry out really fast.
It's also a bit of a challenge to plant in the back of the Crocs which are open. I usually line the back with moss so I can stuff in more potting soil.
Crocs also have a heel strap, which is great if you want to hang them on a wall. You can tie each end of fishing line or twine to the straps and then hang the line over a nail - putting them at the same or different levels
It can be hard to find large, inexpensive containers. I look in discount stores, often in the housewares departments. I also look in hardware stores and in feed and farm stores (which are admittedly hard to find if you live in a city).
I keep a lookout for trash cans. Some are only a couple of dollars and are quite clean and modern. They are usually easy to drill drainage hole in and will often hold up for a couple of seasons.
A large sized, brand-new kiddle pool will cost about $9.00. It's a great way to get a larger, really inexpensive raised bed. You can put it on a driveway or on your lawn. If you put it on your lawn, you can say goodbye to your grass, but sometimes it's worth it.
Because they are fairly shallow, I wouldn't try growing giant tomatoes in them. Herbs work really well, as do annual flowers and salad greens.
I don't know why, but there are old colanders at almost any yard sale or thrift store you go into. I love the way they look and the built-in drainage is fantastic. Also, if you can find a restaurant collander (you'd be surprised, they are around), get that. It makes an awesome container for an annual like calibrachoa, also called, million bells.
I love growing flowering annuals in them and also herbs and lettuce.
Flower bags, or flower pouches are a beautiful and inexpensive way to grow vertically. They only cost a few dollars and they look great hanging from fence posts, or on a wall. They look fabulous, hanging in multiples. Flower bags are super easy to make.
You do have to be a little careful of what you plant. One year I tried to grow tomatoes in them, which was a total fail.
Flowering annuals are perfect for these bags, but you can also do herbs and lettuce. Plants that drape, like petunias, million bells, thyme, golden oregano work wonderfully. You can also mix them up. I've also seen them planted with impatiens and they looked terrific.
I love old baskets. I'm always on the lookout at thrift stores and yard sales for baskets. It's amazing what you can find. They often cost just a dollar or two. Some are a little beat up, but have character, so I buy those too. Also, sometimes all it takes is a can of spray paint to a basket and really make it into something special. I buy them in all sizes and colors. Usually they will last a season, but some last a few.
I used to line my baskets with moss, but over time, I have found that the basket lasts longer if you line it with plastic, cutting a hole for drainage in the bottom.