Both lowes and HD can sell you semi-transparent stain, both need to match color. So you go to the shelf to get whatever semitransparent paint you wanted, and take it to the paint station to add some color to it.
You can peel a small piece from your deck to bring in the store to match color. If you can't get a sample, you have to go to paint station to see if they have brochures for deck stain so you can bring it home to match color, something like this: https://www.pinterest.com/pin/408772103691403237/
