If your cell phone has WiFi, it can connect to your wireless broadband router (or any free hotspot). And that's all you can do without a data plan.
Using a PC for Internet Connection Sharing (ICS) for another PC, is possible (although you rarely find someone who got it working). But I sincerely doubt if there's an Android app to support the USB side of the story in the phone.
i have no data plans and want to have internet access on my phone through PC via USB as i have broadband connection
details of phone: Samsung Galaxy Y
Model : GT S5360