Cari, I disagree. Leon sent me a 750 a few months ago as a donation for my kids. It worked. I cleaned it and oiled it. I took it to school and the gears under the bobbin disintegrated in about 2 weeks.
If it's a donation, you have no idea of how the machine has been treated and stored. My 778 is still going strong, but it has always been stored in the house and has not been used much. You have no idea of how a donation machine has been stored or used.
Of course, we don't know what makes the gears crumble. Is it just age? Does how it's been stored make a difference? If it's been used heavily, does that affect it? We don't know. You certainly can't speculate about one you find in a thrift store.
$25.00 is not all the money in the world. If the seller is a charitable organization, you can't lose. However, after dealing with a lot of touch and sews, I'd assume it will last a month or so after you start using it. $25.00 for a few of weeks of sewing is pretty expensive. If you want to donate to their cause, that is different.
As far as the accessories, it's nice. However, I would guess that very, very few of these T&S machines will be working in 20 years. There will not be much of a market for the accessories in the future.
Of course, it's just my opinion.
bkay