Jump 2.0 and Promotion

I have paid off half of the price. now i want to upgrade, when i try to upgrade that i have two options. one is keep jump that i have to pay $45.84 monthly for 24 months, the second one is i have to pay balancre half of the price to be paid off. it’s only $4.17 monthly for 24months, is that really true? seems like scam or something like that. please make me clear this i am so confused with this.