I'm confused by this statement "Your Forge account is billed based on how much bandwidth you use. On our basic plan, if you stay under 10GB each month, you'll o

I'm confused by this statement "Your Forge account is billed based on how much bandwidth you use. On our basic plan, if you stay under 10GB each month, you'll only be charged the base rate of $10." Is it that I only pay for what I use or is it a minimum $10/month charge? Right now with https://www.nearlyfreespeech.net/ https://www.nearlyfreespeech.net/ (and similar to AWS) I really only pay for what I use. With NFS I deposit money and based on my usage each month money is deducted. Please make it clear if I'm billed on usage or charged a flat rate.