E to PE

I'm new to the site, and the forum, and must say it's great!
I'm travelling on business to Miami in July, company wanted me to find the cheapest ticket so I did. It is an N class economy ticket.
My questions are, am I likely to be able to pay for a PE seat on the day and, if so, can anyone give an idea of cost?
Thanks for your help.
I'm travelling on business to Miami in July, company wanted me to find the cheapest ticket so I did. It is an N class economy ticket.
My questions are, am I likely to be able to pay for a PE seat on the day and, if so, can anyone give an idea of cost?
Thanks for your help.