Have any of you handy ladies refinished your own tile? Or have you redone your grout or caulking before?

I kind of want to try a DIY job changing the color of our tile in our stall shower. It's a small space and the tile is in good shape, so it seems like a good DIY experiment.

Has anyone done it? I got a quote and the price was ridiculous and I inquired about the process and it's exactly the same process as one of the $50 kits they sell at home depot. They quoted me $2k for a very small tiled area.