Let's suppose that you buy one of my 7 x 7 cm canvases. What are you going to do with it?
You could put it away in a drawer and take it out to peer lovingly at it every now and then, but I'm not sure that that's quite the idea. I rather suspect that you might like to display it in some way.
Now, as an acrylic on canvas, the usual approach is to treat it the same as an oil on canvas. It doesn't need to be put behind glass; all it needs by way of protection is a coat of varnish, and it should already be varnished (I've still got some to varnish, but they should all be done in time for the school fair next Friday; you can varnish acrylics almost as soon as they are painted, because they dry quickly). The canvas doesn't really need a frame - as noted earlier, I've painted the edges on the assumption that it won't be framed.
But actually displaying such a small canvas presents its own problems. Do you put it on a wall? And how? I'm not selling them equipped for hanging, although I have got a suggestion as to how you might hang them (and I can provide the hardware*). You might prefer to display them resting on a small stand - one of my friends mentioned plate stands. Miniature display easels are another option.
In the past, I have prepared smaller canvases for hanging by screwing a D ring on the top support so that the "D" is uppermost, but the supports for these canvases are too thin for that (the D ring would be too visible). However, I have found that it works equally well to point the "D" downwards and then use the plate's natural hinge to point it upwards. Here are two I prepared earlier:
The larger brass D ring on the right is one of the type I already had several of. But I thought that a smaller ring might work better, so I have invested in a few smaller, triangular rings.
* Of course, if you'd rather buy your own, small quantities of limited types can be bought from all the usual DIY multiples. Or you can visit an online dealer like UK Picture Framing Supplies, who have a much wider choice.