Cheapest Way to Prevent Rust In Small Scratches

Edit: I realized there is another area of the site that is probably more appropriate for this post, so I'm copying it to there. Moderators, feel free to delete this if you see fit, sorry for the inconvenience.

Hi all,

I've managed to get a number of very thin, but deep (seems to be down to the metal), scratches on my car over the course of the winter. Aesthetically, I don't really care that much, however, I do want to protect against rust. On the other hand, I do not have much money at all. Do you think I could keep applying clear nail polish every few months to keep them rust free? Or am I ultimately just going to need to suck it up and replace them?

I'm just looking to keep the car healthy, I don't care about pretty.

Thanks

You can prevent rust in small scratches by applying light mineral based oil that will creep into door seams, folds, joints and weld spots where rust often starts. Oil based sprays displace moisture and can be applied to a wet surface. This, combined with thicker gel type oil for the under-body, wheel wells and rocker panels, will provide optimum protection against road salt. Rust proofing oil also protects your electrical components, brake and fuel lines against corrosion. Road salt will not damage your winter tires, nor will this oil application.