No need to invest any money with HubPages. HubPages do not directly pay you for your writing. You can earn money from following affliate programs when they display ads in your hubs.
Following affliate programs are currently available with HubPages. If you do not have an ID from those, you should log in to those first if you want to earn money. Before applying for these programs you should at least write 1 or 2 good quality hubs.
Hope this answer is helpful to you. If you need anymore help just let me know. I always happy to help you.