What can you do if the domain name you want is not available?
As per as I know domain name very importance for any website for several sense. And for establish brand name, domain name very importance. Beside your domain name will help to other for searching according to what they want. And I think on-page SEO should start with domain name too. But, what you will do, if you do not get domain name of your choose? I think you will not leave the name, if you do not find domain name with your existing brand. And may go for buy from other who already purchased before you, I mean from current owner. And it is common sense that person who you will see the listed, he should charge more then as normal price.
On the other hand, you have to try to get other similar alternative domain name with cheap price. And that should be best option for you.
So, what will you do? Will you go for purchase domain from current purchaser with high price for establish brand name? Or , Will you go for search alternative domain with cheap price?