2001 Chevy S-10 Check Engine light

Electrical problem
2001 Chevy S-10 Manual 43000 miles

Took the truck to a trusted mechanic, and after diagnostic, told me nothing wrong with vehicle except the fuel sensor. However, I am told that while the sensor is relatively cheap, less than 100 bucks, the labor may be 500-700 dollars, as that is very extensivework m also told I cannot pass inspection if this problem is not fixed. Being unemployed for 10 months, that kind of $ is hell to pay out for a damned sensor. I should also mention they reset the sensor, and told me to drive on it, and now sometimes the Engine light comes on, sometimes it is off. But no troubles with the vehicle otherwise. Anyone help me with a simple solution? Or will I just have to bite the bullet and pay up on this? Thank you.