$39.95 a month for the first year. Promotional rate offer available exclusively to Cablevision customers who order on Optimum.com and install it themselves, one account per household. Primary account only. Includes free shipping of the self-installation kit. Service on additional modems will be billed at the regular Optimum Online rate. Billing begins within one week from purchase. Service will be billed at the regular rate on all accounts as of the 13th month. Prices and terms subject to change without notice.