Probably better to do $10/year thsn $1/month... Maybe have a shorter first increment for people that don't want to risk $10...
replyBunny.net has a similar model and it's nice (Top up the account and minimum $1 per month).
replyThis website also has a pricing model that is a bit discouraging and quite common in my experience. Nice free tier, thanks, but the first paid tier is a bit far out of reach or not worthy. My only guess is that they are forced to do it this way to fund the free tier.