is it an app that lets u get on even if there is no wireless near? so if i'm on a faarm it will work?

No, Boingo isn't a magical application that'll get you networked with no network.. unfortunately.
Boingo is a company which collects and makes deals with network providers, which could be wi-fi, mobile phone networks, anything. So, if you hit upon a wi-fi hotspot, or a phone carrier network, any network, which has a deal with Boingo, then you can log on to that network with your Boingo credentials (on devices where there is a dedicated boingo application available there is also an amount of auto-login). So, you pay Boingo, and Boingo pays the network provider according to their internal business deal.

The idea is that it could be cheaper for you than dealing with paying the network provider (hotspot, phone) directly.

NO, the only way to "get on" is with a tethered cell phone, if there is no wifi. You can search under "tether" or "tethering" to read about this (also, try "DUN").