2007 Macbooks without the "Pro" moniker only can download one operating system, and that's only if they have 10.6.6 to 10.6.8 preinstalled by DVD and Apple's software update.
If they have that, they can install Lion via App Store download.
Before you install Lion, you'll need to install Snow Leopard 10.6.3 retail installer disc, by purchasing it from Amazon or eBay.
The disk looks like this:
And does not say Upgrade, Dropin, or OEM, or any specific model.
Realize that Snow Leopard offers compatibility that Lion does not, and that may be useful before upgrading to Lion.
See my tips:
Snow Leopard installation questions.
Lion (10.7) upgrade questions - Apple Community