I've bought many times through Fidelity, I generally place the order at the ask or round up to the nearest penny as if I want the stock I don't get concerned about tenths or hundredths of a cent. I place limit orders generally GTC, but it's rare that I don't get it the day I put in the order for stock. It's very different for options, there the spread is often far apart and I'll put in an offer somewhere in the middle, sometimes it takes weeks or longer for the entire order to fill, occasionally it never does and if I really want more of the option, I raise my price.
Did you track the price, it's likely the ask went above your offer practically as quick as you placed it. If your order is GTC you'll probably get it on any weakness unless the stock is up dramatically from when you put it in, if that's the case, raise your price if you really want it.
Most of the time, I've found that Fidelity actually fills most orders below my offering price, but only by tenths or hundredths of a cent. I frankly preferred it when about the smallest increment between bid and ask was 1/32nd of a dollar, trading down to hundredths of a cent has made it lucrative for computerized trading which I believe can be more manipulative than when much larger spreads were applied, even for penny and sub-penny stocks. Perhaps sub-penny stocks existed back then, but I certainly wasn't aware of them.
Today I find many investors who just don't see where a penny stock moving from say a quarter to a dollar is far more lucrative than a blue chip, like Tesla going from $200 to $250, $300 or even $400, it would actually have to go to $800 to make the same percentage gain. Percentage gains is really all that investors should look at, if you get a 1000% gain it doesn't matter the price of the stock, only how much of it you own. Many investors I know won't touch a stock trading for under $1 or even $5. Many consider anything under $5 to be penny stocks.
Gary
