doesnt anyone know the price of an i7 i cant find anything on the net.
No, no one knows yet but Apple.
People have been asking for the BTO options (i7 upgrade, RAM upgrade, Fusion/SSD upgrade. 680MX GPU upgrade) since they were announced in October and so far, no one knows for sure.
We have a ballpark for some things based on the prices for the Mac Mini upgrade (Fusion drive mainly) but the specific cost of iMac upgrades is so far pure speculation.