Go to check capacitor
Likely the capacity has gone bad.
If you know how to replace it and can get parts, cost is $25-$50 depending on the brands.
If you need to find A/C technician to do it, cheapest is $80, reasonable is $120-$140, over $160 is in expensive range.
If you are in high living cost area (bay area, DC, NY), you need to add another 25% more.