A few useful phrases

I've exhausted all the vocabulary in chapters 1 and 2 of my book, but I still have quite a ways to go on hiragana characters to catch up... I'm slow with the hiragana. The words stick in my head easily, but the hiragana not so much... I have my あいうえお / かきくけこ pretty firmly in my mind, but only if I do them in order... Well, practice makes permanent, as an old band teacher of mine used to say, so I'll just have to keep working away. Also, my character of the day is さ - sa.

Here are my phrases of the day:

Ii desu ne. - That's a good idea. 

Irasshae(mase). Welcome. Can I help you?

Soo desu ne. - I agree./That will be fine.

Ittekimasu. - I will go and come back.

Itterasshai. - Please go and come back. 

These last two are said when leaving home for the day to go to work or school or whatever. You wouldn't say sayoonara because that's just for leaving in a permanent/indefinite sense.... ittekimasu is for 'see you soon' type situations, I think. And itterasshai is what the person who is staying home gets to say, as far as I can tell.