A tool I've loved for business is Dubsado. Not only because it has a client portal to use for clients, but because of the way it moves a lead to become a client (and also keeps track of client projects as well).
Ways you can use Dubsado to grow your business:
Right now, they offer it for $30 monthly (instead of their normal price of $35 monthly) or $300 yearly (instead of their normal price of $350 annually) this week only, until February 28, 2020. Learn more at www.dubsado.com.