Hi allI've been reading that one should never commit more than...

Hi all

I've been reading that one should never commit more than 20% of a portfolio on a single share. All well and good. But I only have $5000 to invest in total. So.... $1000 per position.
Am I pissing in the wind even considering only investing $1000 per position? Do I really need a beginning amount of $20,000 or more to even dip my toe in the market? Is that a myth? Have any of you made money with starting really small? I have to start somewhere and I just don't have the big bucks. Constructive feedback welcome. Many thanks