This year the mexicans got two direct spots to the Copa Libertadores and an extra one in a playoff game against a weak South American team. Prior to the playoff the mexicans had their own playoffs with about 6 teams I believe... and I don't know on what basis those 6 teams are picked by the mexican federation (I guess whoever has more money). In previous years mexicans got only two spots but now that they paid alot more money to the Conmebol (South American federation), they let an extra one through this playoff thing they had for the first time ever in Copa LIbertadores history. So this format could change at any time. I'm sure if the mexicans payed enough money, they could get at least 5 teams in there, the amount brazilians and argies have. So in the end, an answer to your question is $$$$$$$$.