OK. $250 is decent number to work with. But before you spend any money do this: flip the rear view mirror upside down and improve visibility out the windshield - won't cost you a penny.
As far as accessories go and where to spend that money - How do you use the Jeep? Daily driver? Weekend warrior? Is there anything that seems like it is lacking for how you use the Jeep? Functionality? Security? Comfort? Bling? What?
There's a crap ton of things that you can buy for a YJ that cost less than $250. What's useful for one person, is worthless to another. It'll be more efficient use of our time and your money if you kind of have an idea of what you want/need, so we can suggest inexpensive options that meet those wants/needs.
If you have no clue at the moment, you can browse here: http://www.quadratec.com/
for ideas, or choose from the companies found here: Jeep parts
. I'm certain you'll find inspiration