Need advice about configuring subdomain

[Flash Love]

I have a domain and website hosted at an ISP, now I want to bring my home
linux box using DSL online as a subdomain. The ISP advices me that I need a
static IP to accomplish this task.

I have found that the monthly static ip expense far exceeds the annual
yearly fee that I am presently paying for the hosting service and domain
name combined.

I understand the ISP's desire for a static ip, however, I am now wondering
if running a slave DNS locally and using a service such as zoneedit or
no.ip would be sufficient?

Flash