I can help with some ideas on paid options but if your budget is limited, the best thing you can do is have some solid strategy on garnering positive reviews. We've used some genius ones I've learned over the years to help, especially on new apps. DM me if you'd like to talk!

Optmyzr, no question. It was built by the ex-adwords evangelist at Google and is all about productivity. DM me for more info, we use it day in and day out on my team.

I've worked on the Agency side for the last 8 years and it really depends on your spend levels and the complexity of what you're trying to achieve. At the least you'll be looking at $1,000/mo for someone (likely a contractor or small shop) who will spend real time on your account and that will scale up if you're spending more than $10,000. Agencies usually have minimums of $1-5,000/mo depending on their own size. Feel free to message me if this was helpful and you'd like to know more.

Depending where you live there is a great organization I teach for that has locations all over the US. It's called General Assembly. Website: https://generalassemb.ly/
I teach a Data Viz 101 there but they have, at the very least access to, lots of professionals who are more than qualified to help you out. I may be able to help or, depending on what you need, can put you in touch with someone who can.