This is the 10816th most frequent Russian word.
выгодный
Profitable; beneficial; advantageous.
In this context, the word "выгодные" describes prices that are favorable and beneficial to the buyer.
Этот магазин предлагает очень выгодные цены.
This store offers very advantageous prices.
Here, "выгодно" is used in an adverbial form to indicate that an action or decision brought a positive outcome.
Заключить этот контракт было очень выгодно для нашей компании.
Signing this contract was very beneficial for our company.
In this sentence, "выгодный" characterizes a method as being optimal and yielding the most beneficial results.