Groups should occasionally increase prices. Members react better to less frequent, larger price increases as opposed to many small increases. The emotional stress of paying more is often higher than the financial burden.
To increase prices on Heylo, create a new membership plan with the new price. If the price increase is uniform for all members, move the existing members to the new plan. They will be notified and charged accordingly.
If the price increase is only for new members, make the existing membership plan hidden and make the new membership plan visible. New members will only be able to see the new membership plan and price when signing up.