Gardening can be expensive, yes, but it can also be inexpensive, in large part depending on the choices we make.
Do we need new tools or will old ones do? Do tomatoes need a fancy trellising system, or will some sticks and twine work? Do you need to buy squash plants at the store, or will squash grow just fine if you stick some seeds in the ground? Does your garden need to look like a magazine cover in its first year, or can it be a bit scraggly and sparse for a few years while you slowly add to it? Do you need to purchase all your plants, or is there a gardener nearby who might be happy to share?
On that last point, I can almost guarantee you there is someone who would be happy to give you plants. Every gardener I’ve met has been thrilled to split a clump of flowers or hand over an envelope of seeds, all the while sharing their knowledge and enthusiasm. Nature is generous, and good gardeners are part of nature.