There are more options than that. For instance, to obscure a planned increase from $550/month to $660/month, the offer could be two months free: 12 x $550 = 10 x $660.
There's no reason the discount has to be for the full rental amount in a month. To obscure an increase from $550/month to $575/month, the offer could be be $300 off for January: 12 x $550 = $275 + 11 x $575.
There's no reason the discount has to be for the full rental amount in a month. To obscure an increase from $550/month to $575/month, the offer could be be $300 off for January: 12 x $550 = $275 + 11 x $575.