using other markets price

I am web designer and i want to design a market. i recently heard that there are some way to get your price from another websites that have the same product or some think like that. i have a huge search and finally i decided to post my problem here. i know we can load other site like below

 <iframe src="http://www.someshop.com"></iframe>

or

 <FRAMESET cols="20%, 80%">
    <FRAMESET rows="100, 200">
     <FRAME src="contents_of_frame1.html">
     <FRAME src="contents_of_frame2.gif">

or other ways

but its not working i think. but i don't know what the tech is. i will appreciate any info.