Tricky question to answer! Eligibility for course funding varies from country to country, and indeed between provinces/counties and even cities.
You should speak to your local careers office, job centre or whatever government department is responsible for education and skills.
It’s also worth speaking to your chosen CELTA centre, as they will know if any other students have qualified for a grant.
Finally, if you have been working without a CELTA at a language school, they may be open to sponsoring you by contributing to your fee.