These ebay sellers are making a huge markup on kit that cost between £10 (for the £39.99) and £16-17 (for the £59.99) sets.
The installed software and games are all available for download from the internet.
In addition to these kits to use 95% of the games you'll need a Ram upgrade, this will cost you between £30-£60 depending on supply/demand.
An A1200 with a 4gb CF Card installed on a CF-IDE adapter with 4mb/8mb Ram Upgrade would be ideal for enjoying all those classics staight off the CF card.
The old Floppies may or may not work, depending on how dry the sorage conditions have been over the years.