If you want to limit yourself to a 500-700 machine, then do that. You can buy used macs, refurb macs, mac minis, etc. There is no requirement to spend 1200 on

If you want to limit yourself to a 500-700 machine, then do that. You can buy used macs, refurb macs, mac minis, etc. There is no requirement to spend 1200 on a mac to begin development. There is no requirement to get a DUNS number to develop on the App Store. As far as a server certificate goes, there is no $175 certificate for notifications. However, if you are running a web service it would be sensible for you to acquire a SSL certificate, regardless of what platform you are developing for.