Selecting the correct price
Variable naming is very important for readability.
Now, as some background, when I first saw your question, it had the title:

What are your opinions on my javascript function?

Titles like that are an poor choice for code review, and as a moderator, we actively change titles like that to reflect what the code does, and not what the question asker sees as being the problems in the code.
Unfortunately, when I read your code, to try to see what it does, all I could think of was goofers... it took me a few moments to understand that the code was meant to be &quot;go offers&quot;.
camelCase to the rescue...

gooffers should be goOffers
scope.returnoffers should be scope.returnOffers

Apart from those two, all your other variables are correcly cased. The following are good:

tarifSecondeFlex
tarifPremiere
scope.selectedGo
goPrice
etc.

Note, I believe you have mixed some natural language variable names in there. Is that French? In general, when programming, you should pick a language, and stick to it. You have a mix. Since you have goPrice and selectedGo which appear to be English, I would expect tarifPremiere to be primaryPrice, etc.
Language consistency goes a long way toward readability.
DRY code
Repetitive code is often an indication that function-extraction would be useful.
Consider a function like:
function selectedTarif(component, selection) {
    if (component == null || typeof component == 'undefined' || component.id !== selection) {
        return null;
    }
    return component.tarif;
}

Then, your code can become a cascading 'falsy' test:
var updatedPrice = selectedTarif(scope.goOffers[go].tarifPremiere, scope.selectedGo)
            || selectedTarif(scope.goOffers[go].tarifSecondeFlex, scope.selectedGo)
            || selectedTarif(scope.goOffers[go].tarifSecondeNoFlex, scope.selectedGo);
if (updatedPrice) {
    goPrice = updatedPrice;
}

var updatedReturn = selectedTarif(scope.returnOffers[go].tarifPremiere, scope.selectedReturn)
            || selectedTarif(scope.returnOffers[go].tarifSecondeFlex, scope.selectedReturn)
            || selectedTarif(scope.returnOffers[go].tarifSecondeNoFlex, scope.selectedReturn);
if (updatedReturn) {
    returnPrice = updatedReturn;
}