Another option is to search on the freelance/upwork websites as well on here. The main prerequisite should be the work commitment of the developer(s), as people have mentioned expensively priced developers doesnt necessarily guarantee satisfaction or commitment.
I have spent the last 10 years working with software development teams in Sarajevo, Bosnia, both as employees of our wholly-owned subsidiary and in an outsource model. I have found the technical talent there to be very strong and English-speaking - so good in fact that this is my third company using software devs in Sarajevo.
As my new company is small and self-funded (and I’m not a developer), I wanted an outsource dev shop and went back to Sarajevo to find the right one. In my search, I was introduced by a trusted friend to a team in Sarajevo that I cannot recommend more highly.
They are super smart technically, English-speaking and have a strong skill set covering a range of capabilities including front-end, back-end, UI/UX, security and native mobile. Most importantly - they are very collaborative. I work with them the same way I used to work with employee developers - we work collectively as one team. If there is a problem, they do what it takes to get it solved, regardless of the hour.
They are based in Stockholm and Sarajevo and have built a number of impressive projects in Europe. They are busy and selective and prefer longer term engagements, but have interest in expanding their client base to the US. If this sounds interesting message me and I’ll make an intro.
Don't worry too much on the pricing, instead think more of the quality terms. As the prize increase so will it be with the quality.
There are too many philosophical answers to the specific question.
The answer is east Europe - Serbia, Ukraine, Bulgaria etc. etc.
You will get deal "best buy".
What it "best buy"?
The developers in east Europe aren't the best developers and for sure not the cheapest, but for very reasonable price you can get excellent quality.