My first calculator was a Texas Instrument SR10. I knew people who had paid up to $150.00 for one but I waited till the price dropped to $30.00. I remember thinking I've got you this time, the price may drop a little more but no way can it ever drop very much more. A year later it died while still under warranty. All I had to do was to mail it back to Dallas and they'd send me a new one. Problem was postage would have cost more than a replacement from Sears that would do all the same things.