How can i make a shop where you walk up to an item and click a button such as "e" to buy it?

over all i want to be able to interact with an object by walking up to it. once i walk up to it it should say "e" and then when i press it such and such will happen. like filling up gas, opening doors or buying food. It doesnt just have to be "E" it could be another key. i just want an key activated interaction.

1 - Create an object and gives it a Value with Unique name

2 - In a block around the Object with the distance that you want for the letter to appear

3 - Create a "BillboardGui" and, put the letter either and Modify any way you like (if you prefer you can only use "StarterGui") after doing this and put in "Lighting" and give it a name. Then Make a Shop Gui.

4 - Create a variable with any name.

5 - Add a script to the player, use Touched for when the player touches the block the variable is set to true, Billboard is cloned and appears. And use TouchEnded to disappear and variable is set to false.

6 - Then create a function for when you press the letter E and the variable is set to True, the letter will work

7 - Make the script get the Object Value for Find his Shop or somenthing else.

8 - When you press the letter, Shop will open.

9 - Be Happy.

This is an easy way to create this and it is just nescessary little programming knowledge.