I live on a tiny island (~20 miles long) and I want to buy a bike that is good to use on dirt trails and some sand trails. Pavement and tarmac a given (often with sand on them). I'm not trying to bike on the dunes or anything but, thin wheels won't work. Also it's illegal.
My budget is about ~$500, cheaper if possible. Used is fine.
I'm 6'3".
>buy a local used bike
There is no used market within 40 miles.
There are a few people selling what amounts to scrap on wheels but, they're too small for me anyway.
The trails aren't particularly rough so a rigid frame should be fine.
I don't know much of anything about bikes though hence why I'm asking for suggestions or I'd end up buying the cheapest option from a recognizable brand.