I just cant afford the monthly if it was a one time payment I could afford it
This doesn't make sense. For example, Adobe's Master Collection (most of their latest programs) used to cost $2500 USD as a one time payment, and then when they came out with a new major version, they'd offer a discount to existing license holders to upgrade, though it was still expensive.
Later, they changed to a subscription model, which I believe is/was $50/month USD for full access to what had been in the Master Collection. Paying monthly, it would take 4 years and 2 months to equal the one-time cost of the original Master Collection. The advantage was simply that you bought it, whereas with the subscription, you never owned the software.
I very strongly believe that the best subscription model is the one used by Sketch (the design program for Mac). They have a first-year fee (~$100 or something; I think it changed recently), and that buys you the program along with 1 year of updates. After that year, you can continue at a slightly reduced cost (~$60 or something, I think this also went up recently), or you can hold off on paying. You keep the software, but you don't get additional major updates (most of their updates are "major").
Using that model, you basically pay for each year that you're using the software, but you never lose the ability to open and modify your old files. This incentivizes and empowers the devs to keep working, and it prevents users from losing access to software they've paid for.
Scirra would be even more awesome if they went to a model like this, in my opinion. Still, the current model is totally fine.
Finally -- the notion that you can't afford $8.33/month (the avg when paying by year) seems unambitious of you, if you actually care about this software. If you truly are that constrained financially, then there are free alternatives available, though none that directly compete with C3's offering.