Learn Russian: Тебе придётся экономить деньги, чтобы купить этот дом. - You will have to save money in order to buy this house.

The word придётся (will have to) creates an impersonal sentence. In Russian, when you use this construction to say someone has to do something due to circumstances, the person who experiences the necessity goes into the Dative case. So, Ты becomes Тебе.

Is придётся the future tense, and why does it have a -ся ending?

Yes, придётся is the future tense of the perfective reflexive verb прийтись. When expressing necessity, it is only ever used in the third-person singular form (like an 'it' form) because the sentence has no grammatical subject. Literally, it translates to something like 'it will come to you to...'.

Why do we use the imperfective verb экономить but the perfective verb купить?

This is a great example of how Russian verb aspects work! Экономить (to save) is imperfective because saving money is an ongoing process or a repeated action. On the other hand, купить (to buy) is perfective because buying the house is a single, completed result.

I know чтобы usually means 'that', but here it means 'in order to'. Is that a set rule?

Yes! When чтобы is followed directly by an infinitive verb (like купить here), it expresses purpose. In these cases, it always translates to 'in order to' or simply 'to' (as in 'to buy').