You are aware, right, that a nice day with a 1% gain on a $ 7 stock will get you 7 cents ?
A 1% gain on a $ 100 stock will get you $ 1.
You will have to buy 14 shares of the $ 7 stock to get you within 2 cents of making that $ 1.
If God said I guarantee you a 1% gain today, which will you choose ? Short answer is probably won't make a difference in absolute dollars gained on the position. But why blow a sure thing ? To the extent you have or can get the money, would you rather buy $ 5,000 dollars of the $ 7 stock or 50 shares of the $100 stock ? Either way you are paying five thousand dollars.
Consideration:
Would you rather pay commission on 50 shares of the $ 100 stock = $5,000 ?
or
pay commissions on 714 shares of the $ 7 stock = $4,998 ?