Direct Answer:
You can't really get cheaper than Upwork or Fiverr or Craigs List. And you'll get what you pay for.
Since you have a starting point (your competitor's site), you could do it yourself on paper: print it and draw your edits, then give it to your front-end dev. (with their code pulled from their page, if you need to).

Longer Answer:
I deal with a lot of startups that hope to build a digital product that's a "better" solution.
I'd caution you: only IF and AFTER you have figured out on your own what your potential customers/users need, and have concluded that the compeitor's site meets (some of) those needs (even if partially) should you use a competitor's actual visual UI/UX design as your starting point Otherwise, you'll just expend effort to make their poorly fitting design less poor. To get and keep customers, you need a GREAT UX, not just a better UX. No customer is happy with a poorly fitting UX that fits their needs less poorly than another business.
Analyzing your competitor's product/service to make your own design fit your customers' needs well, is smart. Copying their design, might not be.

If this helps and you want more guidance and specific design advice, get in touch here about having a short intro call.

Hi, the best practices for this are pretty specific to the particulars. You asked your question 23 days ago. Are you still looking for an answer here? Let me know and we can take it from there.

I would have to ask you a few questions of my own to make sure I understand what you need advice on. Since you asked this 5 months ago, I want to first check that you are still looking for an answer here, from a Clarity expert. Let me know and we'll take it from there.

You're question is thoughtfully phrased. You asked it here 8 months ago. Are you still looking for help with this? If so, let me know and we'll take it from there.