Hi Roger remember that before having a pro demo made you have to have something worth demoing and someone to pitch it to.
You must also be prepared to write the money off that you spend on the demo as 99.9% of demos get nowhere.

Re buying equipment etc. Buy what you want an can afford. But treat it as a hobby and have fun. Few will ever make money from songwriting.
That does not mean you give up hope and stop trying. Just be aware.