As XBCG surely we don't want to spend money in translators, so we usually support english and our native language at first, but many times I see bad translation in commercial games, so I'll expose cases so you could say what one likes you more:

1. Use a computer translator (like google translator) at beginning and, if game gives you profits, pay a good translation, and then update the game (for that I post Can be XBCG be updated).
2. Support only english and your native language.
3. Use a computer translator (like google translator) and that is the final version, with no worry about if is a bad translation.

What one do you think is the best option?

Unless you know at least a bit of grammar in the target language, I would advice against using any computer translator. Consumers will not appreciate badly translated games, and might not buy your games in the future. Of course, some people will not get mad, and will play them in english, but that's the ideal case.

What do you think, is better insert a bad translation with possibility to ignore it (force to load english) or simply not insert it?.

Dark Schneider:

What do you think, is better insert a bad translation with possibility to ignore it (force to load english) or simply not insert it?.

If you're going to have multiple languages, you might as well place that option in the Options menu, and have an option to choose language, rather than "Force English"

Personally, if the translation is bad, I'd rather not even have it as an option, but I'm sure lots of people feel different.

Bottom line is, you have to make your game shine in a small number of minutes. A user is likely not going to spend more than 5 minutes before giving a first judgement on your game. And in these 5 minutes, it's not likely they're going to go to the options screen and switch to english if they don't like the translation. And a bad language experience could reduce their willingness to buy the game. So for attracting customers, I think you should either have a top-notch translation, or leave english as the default (with the option of changing it later). Having the bad translation as default (even if you can change this in the options menu) might turn off customers.

There's another option:

4. Get a native translator who will volunteer the service for credit in the game.

Make a good game that people want to play, and people will also want to share it with friends. If most of their friends only speak Portuguese, they may very well be willing to do a translation just so they can share.