Welcome to the community. 
You can earn a PC by getting a job and working for one, just like everyone else has to.
Even if you’re not an adult, there is plenty of work you can do.
Teenage (13-16):
- Car washing
- Lawn mowing
- Newspaper delivery
- Leaflet/pamphlet delivery
- Some retail positions
Under 18:
- Dishwashing at a hotel or restaurant
- Waiter at a hotel or restaurant
- Server at a fast food restaurant
- Most retail positions
- Buying, refurbishing & re-selling old furniture.
If you have the skills, there is also:
- Etsy seller
- Zazzle seller
- Graphic design commissions
- Art/portrait commissions
Best of luck in your job search and quest for a PC.