Pre-assembled (4pc) linking charms would be $30, $25 ea for 2+, and $100 for 5 (Buy 4 Get 1 Free at the discounted price). It's $7.5 per piece at base price -- I may sell individual charms for $10.
Linking charms would be pre-assembled as listed, ALTS would be free to swap with any digimon in that line