I don't remember exactly how much it was, nor if it is the very best I ever spent, but I sure remember 1979 and buying a TRS-80 at Radio Shack.
I hung around Radio-Shack like a teen age haunts the mall. I could always find something electronic to captivate me, from build it yourself kits, to parts, or just plain wire and solder. And there sat TRS-80, a computer. A what? A computer.
I tried to use it like a calculator without results. I asked the clerk why it couldn't add. He said, "You didn't tell it to print."
"That's dumb," I said, "What did it think I wanted to do?"
"Adding is too easy," said the clerk. "Look at this." He typed for a second and it printed out multiplication tables from one to twenty-five instantly. My mouth dropped open. I was impressed and hooked. After a few more demonstations I took it home. I don't remember what it cost, but it was around $495 I think.
I got it home and set it up about four in the afternoon. I didn't get up to eat or even go to the bathroom until ten pm.
Within a couple of days I wrote a program that presented a little multiple choice quiz, checked your answers and gave you a score. I used the entire four K of memory. I saved the program to tape, and proudly took my program to show the clerk at Radio Shack. He gladly gave me a replacement tape for it, and kept it to demonstrate the computer. He later told me my demo tape had sold a computer.
Before long I upgraded to a 16 K memory. And that was how it started. I joined a TRS-80 club. We swapped programs, and tips, and even built a modem for the 80. Imagine building your own modem that worked an amazing 128 bps. Not 128K... just 128.
That was the start of hobby that is now the center of my life. I involved that TRS-80 in my teaching. Then another and another, and then ATARI and TI-99 and APPLE. I have had dozens of computers since, but none more fun than the first TRS-80, which I programmed myself in BASIC.