Do you both mean a midfielder in addition to Kagawa? As in a solid, tackling defensive-esque midfielder to Kagawa's creative midfielder?
I don't think it matters how much money Fergie has, if he doesn't think there's value in the market he won't sign anyone for the sake of signing them, to appease the fans or to spend what transfer budget he has. He's said this before hasn't he? When we've not signed many players over a summer.
Some in the media and in here suggest Kagawa is as much a 2nd striker as he is an AM, so if/when Utd finalise the deal will Rooney be puhed further forward with perhaps 2 from Young /Nani/Valencia on either side?
If this is the case then two AM's like Kagawa and Cleverley wiht Carrick ahead of the back four would imo be a good 1st team (ignoring the defence obviously)
I personaly think Kagawa will be an AM, which possibly means a 4th striker being purchased, I wouldnt be surprised if a box -to -box midfielder arrives too (especially if Anderson is to be sheperded out the back door at the same time).
However with no real backup for Evra at Left back, I would suspect this is the next priority this summer. Media speculation about Baines and Modric is just that, (without knocking either player) I dont believe Utd are looking at either player.
Clyne was linked earlier in the summer, but that has gone quiet for some time
Relatively speaking if anyone is purchased they are going to be moderate to cheap purchases rather than mega-names imo with priority as follows LB, striker (as Fergie always prefers to have 4) and then another midfielder.
Of course it is highly dependant on who is actually available and cost once club knows Utd are interested, but 3 additions incl Kagawa would be a good summer, 4 (which is absolute max to join 1st team, not incl Powell if this happens as he will be immediately loaned back) would be brilliant.
All the above baring in mind Utd are waving good bye to (or have in the last 12 months) PIG, Berba, Owen, Pogba, Morrison & De Laet for definite with question marks over Fryers (has he re-signed yet?), Anderson, Park and potentially Fletcher due to illness
Admittedly majority of those barely played a game, but its still 40% of the squad
edit - you are dead right about "value in the market", without a doubt. This is why (I dont believe) SAF will be that bothered about the Euros, because the liklihood of the players being in the national teams is small imo (baring injuries)