There are several different ways to do this and they will all work. Most of them will cost less then $100. We could possibly make it happen for $20 or $25.
First you want a microcontroller. PICs and AVRs are both good. I can help you with PICs because that is what I use. Either would work for you (and most) applications.
The micro controller can be done several ways. You can buy a micro controller with a built in BASIC lanugage for about $20 to $40 dollars. These do not require a programmer but are often less powerful then other choices. But they are not a bad choice if you are only going to do the one project.
The following choices allow you to program inexpensive PIC chips that range for about $2 to $10. These tools will allow you to program in C, BASIC, or assembler languages which are free if you pick the correct chips (microcontroller).
The second choice is to go with an PICkit2 programmer for $35 from
Product Search - microchipDIRECT.
In place of the PICkit2 you can get a JuneBug which is a PICkit2 clone with a built in experimenter/target board. If you wanted you could develop you entire applaction using just this tool. You can get assembled or as a kit. See the link in my signature.
If you want to go very cheap you could buy a simpler less capiable programmer tool starting at about $15. I do not suggest it but it is an option.
I know that is a lot of choices. If I had provided my best solution additional posts from other members would follow to fill in what I left out.
If you want to learn to program I would go with the Junebug. I use them in the high school computer class and like them.
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