Hi, you need to use Iif and DateDiff, add a calculated field as below e.g.
CurrentPrice:Iif((DateDiff("d",Purchasedate,Date())>365 And <731,[Value of Purchase]*0.8),Iif(DateDiff("d",Purchasedate,Date())>730 And <1096,[Value of Purchase]*0.6),[Value of Purchase])
This does it for the first two...