Ordinarily, the team who finishes fourth in the Premier League would be shifting nervously in their seats at the sight of an English team in a European final. Winning the Champions League is one way of guaranteeing your place in the competition next season, and that courtesy has been extended to the Europa League champions from this year as well.
Normally this would have meant that whoever finishes fourth in the Premier League - either Arsenal, Man City, Man United, or West Ham - wouldn't be rewarded with a spot in Europe's premier competition.
Champions League Qualification
From the beginning of this season, UEFA announced that the country that provides the winners of the Champions League and/or Europa League would receive one additional team into the following season's Champions League. Meaning that in this case, Liverpool would join the top four teams from the Premier League into next season's Champions League if they win the Europa League. This new rule wouldn't extend if one country provided the two winners of both the Champions League and the Europa League and they didn't qualify via the top four places - then the fourth placed team in the Premier League would have to forfeit their Champions League place.
Liverpool will get the added bonus of going straight into the group stage for next season's Champions League by virtue of both Real and Atletico Madrid (the Champions League finalists) have already qualified for next season's tournament via the La Liga.
However, just because Liverpool winning the Europa League won't affect the Champions League qualification of the top four doesn't mean it won't make a big difference to those teams. Those teams that qualify via their league finish stand to lose an estimated £3 million each if Liverpool beat Sevilla.
UEFA rules dictate that the TV money for the English clubs would be split five ways instead of four. That means an average loss of £3 million for each of the top four clubs - who would still get more than Liverpool would.
60% of the money is distributed based on league performance and how well they do in the competition, with the other 40% dependent on the TV deal UEFA has with that country - which is why there isn't an increase in funding with an extra team getting in. English teams will get about £120 million for TV money for next year's competition - with £60 million going solely to the top four clubs based on their league finish this year. The other half would be split based on performances in the actual tournament.