Only the figure is almost certain to reach 90m with the addons mate, and a huge amount of the fee was paid up front which increases the value of the deal in reality.
Was it too cheap - only time will tell, similarly are all those others listed gonna prove to be too expensive - similarly only time will tell. Lukaku is 24 though - not 23, he's also been playing 30+ games every season now since the age of just after he turned 16 (with one season aside), so all the talk about him suddenly improving and ironing out flaws he has had are just talk IMO - you play 200+ games and your still making those same mistakes then you always will do.
Not a hint of bitterness when i say that i think after a initial period of hype and over the top praise at United he will struggle, and end up within 2 years being a scapegoat by the fans for all his flaws, and his on pitch attitude.
We tolerated all that because he was the first out and out goalscorer we've had in about 25 years, if you like we where almost 'too grateful' of his goals and put up with all sorts of put downs and half arsed displays, United and their fans are used to having top class strikers and ones who produce at the top level week in and week out, he replicates his time at here with them and with their manager then he will not last long.