Travel in Peru can be quite inexpensive, if you know where to look. Knowing Spanish can also help you find good deals. Places with English-speaking staff are usually high-end and more expensive.
So if you want a truly budget trip, learn some Spanish so that you can eat in restaurants that only have menus in Spanish and stay in hostels that don’t have English speaking staff.
There are a lot of translators out there, some better than others. If you know a little basic Spanish, I suggest using the online dictionary SpanishDict, rather than a translator.