Trail Running Shoes

I have particioated in 4 semimarathons, 1 marathon, 1 ultra. And I run weekly 50 KM. But my shoes can't hold anyomore, trained and raced in them and they got over 1500 KM mileage. I plan to participate on more marathons and get even better but I need better gear, and currently can't afford the money for new shoes and tax fees for registering on races. Thank you very much