I'm trying to organise a surprise football weekend away for my boyf for christmas (hence why I have had to register with a new username incase he reads this

I'm hoping that I'm going to be able to get tickets to see one of the 'big' teams. I know nothing whatsoever about foreign football but have got it down to four teams; Barcelona, Inter Milan, AC Milan and Real Madrid.
I am limited to the dates we can go, because I know he won't want to miss any games here. There's a couple of weekends in March, and a couple in May we can do. There's also 14th/15th Feb but I'm thinking it will be a bit too pricey. It's also a bit difficult because I have to make sure the teams are actually at home on those dates too.
The thing is, I need to do it as cheaply as poss.
I did find what I thought was reasonably priced flights to Barcelona but just been looking at hotel prices

Also, I'm worried that I'm going to book flights & hotel and not be able to get tickets to the game.
Does anyone have any suggestions, either on getting tickets, or were is best (i.e. cheapest!) to go? I've already got lists and lists of dates, prices of hotels, prices of flights, but I'm totally baffled by it all.