需要買 SMTP server service 嗎?

I created a site with ASP.NET 2.0
I need on time reply features like "forgot email".......

smtp.Send(mm)......

The hosting company charge $3 per month.

Do I need to buy the service to sent email from backend codes?
In other word, is SMTP the thing required to do this?
I'm not a programmer, just do it by myself.

Thanks.