I'd recommend doing it yourself using techniques commonly referred to as 'growth hacking'.

There are a lot of resources on the web to learn, but here is a very thorough and cheap intro: https://www.udemy.com/growth-hacking-masterclass-become-a-digital-marketing-ninja/learn/v4/overview (Sometimes it's only $15, but at the moment it's $30).

In summary, it involves using cheap or free tools and techniques to
1) Get visitors to your webpage (many different ways)
2) 'Activate' them (getting their email address and helping them take predefined actions with your product)
3) Retain them (getting them to be habitual users/customers)

If you'd like to discuss how to implement growth hacking in relation to your specific product, let me know,

best,

Lee