Why, I am sure I shouldn’t be worth a baked onion myself … perhaps with you thrown in.

What baked onion and throw in mean?

Question

Why, I am sure I shouldn’t be worth a baked onion myself … perhaps with you thrown in.

What baked onion and throw in mean?

Answer

baked onion = worthless
thrown in = added to a deal to make the offer more compelling

To loosely interpret the whole phrase:

I'm worthless, and you are too.