Membership does one job: it decides how much of the EZ Deals catalogue is open to you. Gold buying, selling, SIP, transfers and delivery work the same on every plan, including the free one.
Plan pricing is managed by SaveEZ and can change; the app always shows the current price and the GST applied before you pay.
Rates, purity, vault custody and every gold feature are identical on all three plans. A plan is about catalogue access, not about your gold.
Plans are bought and managed inside the app, under Membership. Open Membership.