I don't really agree with the "cancel immediately" way of making a one off donation. I think it should be an actual option.
That aside, I'd be happy to throw a $1 per month with no perks (to help out as OP says). I'm not really up for $5 a month. Is there a reason that the nominated amount has to be at $5 and above. Why not do the Patreon thing where you can nominate any amount you want, but if it's below the minimum for perks then you don't recieve anything?