I think I've seen every marketing pack going, squid, Joe Polish, Ron Mayer, Nuways big book of marketing etc they range in price from £80 to £3,000.
they are worth the money only if you use them. but I've found the same information available alot cheaper.
I think the most important thing to remember in marketing is to know how much you are spending to get a customer, if you send out 200 sales letter which cost £10 to print and £52 in stamps. if this brings in 3 customers they have cost you aprox £21 each. if you know how much it cost to get a customer with all your different marketing stratagies then you know the best way to spend your money.
I know this last bit is slightly off the subject , but it so important I thought I'd mention it
Mike