If they are for sale at $100 per share and you offer $90 per share then they will go in your tabled orders, you won't buy them at that because nobody will sell them to you at $90, only $100.
If they went in your tabled orders say 100 shares @ $90 per share, and then someone put up a sell order for 100 shares at $80 per share, then the transaction will go through at $85..get it?