I would advise don't look out for an affordable marketing expert, but look out for an expert that provides maximum benefit against the cost. I don't think hiring a freelancer may solve your purpose as marketing isn't just marketing, but much more than sum of its parts.

One way could be initiating discussion with marketing experts (Consultants, Agencies) and seek a proposal. I am assuming when you say "Web Marketing", you actually mean an "Integrated" marketing plan with lucid strategy and execution design.

I believe, platforms like Clarity, LinkedIn are good place to initiate discussion with experts and establish an association. Just make sure the resource is ready to invest enough time and energy to understand the situation (Both internal & external to your organization), and strives to design a strategy suited to your business.

Secondly, you need to be clear within yourself that marketing isn't sales, but an enabler to sales. In our experience working with clients across the globe, this is the basic understanding mistake that people carry in their mind.

Do feel free to reach out to me for any specific information that you may be looking at. Need more Clarity? I'm just a call away.