You can save by dropping a second phone line and any ISP cost. Speed is about 10 times faster. I downloaded 27 MB in less than an hour and pages display almost instantly. Convenience is amazing. I leave my e-mail program on constantly and surf instantly.
Security is a problem.
You must learn to protect yourself from intruders. Being on continuously leaves you more vulnerable. You should install a firewall program. I use BlackIce by Network Ice. You can get a free one on the web.