since you have really no sense of how the markets work.

When entering a limit-buy you are declaring the most you will pay. Any price under that limit is valid since you did better,

hence you offered to buy for .155 but there was already a seller@ .151 so you got his shares.

Go into macy's and offer to buy a shirt listed for 25 dollars for 1000 dollars my guess is it will ring up at 25.00 and not a penny more...

or perhaps you'll think that's weird,

or go on ebay and place a max bid 100 bucks above the latest price if not one bids above you you'll win the auction at the lower price

it's all the same