How much does it cost to go from yellow hair to blonde or silver hair?

About $17 at your local dollar general

Bleach and dye are different things. If your hair isn't light enough to tone it silver, they would have to bleach to at least platinum blond. Then they would have to tone your hair, then possibly dye it silver. If your hair has to be bleached, I would strongly suggest seeing a professional to have that done. Specially if you've never bleached or dyed your hair before. 

I had my hair bleached a few years ago it cost about $140. I dye my hair on my own, box dyes can range from $10-$15, it's going to be more expensive to dye your hair at a salon. 

Go on a few consultations and ask them how much it would cost to get your hair to platinum blonde or for you to get silver hair. 

Just to warn you, the up keep can also be expensive. You will nee purple shampoo, purple conditioner and a good deep conditioner. You should also get your roots touched up by a professional. I've been white blonde before, I can't afford to keep it up. I went back to a more natural color of blonde. 

At a salon? Minimum $150.