1-Gaps(spacing) between your upper teeth(front..? Back teeth as well..? )
2- gaps may be due to carries..
We need to examine first.
In 1st case gap can be filled with direct composite(tooth colored filling) or veneers etc. Or orthodontist correction required. Again after examination..
In 2nd case need to take IOPA and filling etc can be done depending on the diagnosis.
Sorry to say this, cost totally depends on diagnosis, treatment planned for you, dentistry is a science so no specific cost for any treatment, might different for different locations, dentist, lots of factors.
Next Steps
Get your teeth examination done. And discuss with your dentist.
Health Tips
Clean any food stuff lodged in those gaps.