well depends on the condition ! and what you want from it - if it's in good chrome then it always makes a sweet summer cruzer - full big pegs and gyro with leather padded seat can make for a good ride
if for a rider - a nice paint work in old school colours can make it look nice as the performer has a different frame shape to some of the bmx's from the same age - again makes for a good looking ride
as for if there worth any thing ! - it's worth more if it has only been ridden lightly and still has a new look - they are not worth as much as 80's bmx's (this is were it gets sticky for what is worth what :? )
again most old school bmxer's tend to go for 80's bikes as that's what they rode most - but some collect 90's rides for there looks or brands
90's bike became heavier, as parts became cheaper and made from chiwain places - more bike where made as companies could do more promotion and make then cheaper to ship to the masses - hence now why 90's bikes are cheaper to buy now and more about
i say 90's bike but this can mean up to 2002 when after that lots more changes to the scene came about, and even more company's could throw out cheap bikes (diamondback, mongoose, DK, and so)
so if it's only a fiver - the condition isn't a pile of rust - you want it to ride and do up - you can always put it on hear to sell ? just a couple of question for you to ask your self
maybe try and get a couple of pictures to put up on here and then we could see if it's worth the fiver
hope this helps - cheers B