AGP cards are still being made [manufactured] but no improvements [ new releases] will ever be made for them.
And you can probably find a good one for around your budget [ I'm in £ so I don't know how much that really is].
But really what I advise you to do is save up and get a budget system that will last you much longer than a new AGP card.
Just a question, what's your PC for.. gaming [ if so, what type - high end, mid end ?] or just browsing the net etc etc