Alec,

Packets can be very lucrative.  I am fortunate enough to have a quantity of Europa 80 packets and they can fetch £10+, so I would definitely recommend collecting them if possible.  The only problem is finding enough at a 'reasonable' price as most punters on ebay now know the value of Panini items.

With regard to Italia 90 I roughly work on a guide of paying 20p - 25p per sticker so I would probably offer about £80, especially as there are no badges included.  As a guide I bought 400 back in 2006 for £72 and I don't really believe Italia 90 stickers have significantly increased in value since then. 

Ian