English not making sense

Still struggling with English here.  (My native language)

Si iba a la peluquería, me gastaba mucho dinero.
If I went to the hairdresser, I'd spent a lot of money.

If I went to the hairdressers:   A possible furure event.   (Not a past event)

I would spend  a lot of money.......  Shorten to I'd spend a lot of money but NOT  I'd spent a lot of money.

I think it is the problem in many languages:  the verb "TO GO"  

maybe better to find another example to illustrate the principles of the lesson

Sorry, but this isn't quite right:

If he had an accident, he won't go to work this week.

If he had an accident, he wouldn't go to work this week

OR

If he has had an accident, he won't go to work this week

or even better

If he has had an accident, he won't be going to  work this week.

Ian is right that the version: "If I went to the hairdresser, I spent a lot of money" is not good English.

The new version: "If I went to the hairdresser, I'd spent a lot of money" is still not 100% perfect.

In its chapter on the use of "Si", my grammar book (by Butt and Benjamin) refers to what could be described as "fulfilled conditions" - which are in fact not conditions at all, but merely another way of saying "whenever" in Spanish.... So in English the sentence above is best translated as: "Whenever I went to the hairdresser, I spent a lot of money".

David:  Thanks for the clarification.  I agree, using "whenever" seems to make more sense than using an "if" clause.  Maybe the problem is that we (many of us) are translating the Spanish "si" as "if" when, in fact, it is probably not "if" at all.  Thank you.

I don't have a problem with the English of "If I went to the hairdresser, I spent a lot of money." This sounds like a logical statement "if X (happened), then Y (happened)" with, I guess the added flavor of knowing that X has definitely happened. "Whenever" seems to convey the same thing. "If I ate seafood, I threw up." Feels like a logical proposition to me. 

I think the best English translation for "Si iba a la peluquería, me gastaba mucho dinero," taking into account Inma's explanation that the "si" clause speaks of something more real than not, would be: "If/When I used to go to the hairdresser, I spent/used to spend a lot of money." Correct me if I'm wrong, please. 

In  my opinion, most of the comments dealt with the English, but the lesson is about the use of "if" in Spanish. If sentences are generally followed by the imperfect subjunctive in hypothetical situations or sentences contrary to fact. However, if the consequence in an "if" sentence is an expected outcome, or a natural consequence, the present or future tense is to be used! The English translations were examples to explain the lesson, particularly for English speakers.