テープでいいです vs テープでいいです - how to use the correct tone to differentiate them?

Question

I've heard native speakers use テープでいいです in stores when they don't want a bag (e.g. they're just buying one item) and prefer that the staff use tape instead. Using it myself has not proved fruitful.

In my example scenario, the cashier has yet to reach for the tape or the bag, so I say 「テープでいいです」and he proceeds to bag my item. My friend has told me that his wife (Japanese) explained to him that it depends not only on sentence structure, but also tone. That is to say that it can be both positive (I would like tape) and negative (no tape, please). So it appears that I must be saying it in such a way that it comes across as "no tape, please".

How can I correctly pronounce it so that it's understood to mean that I don't want a bag and that I only want tape? Is there some gesture that Japanese people use to make this clear?

P.S. I'm already aware of 要らない but I've had mixed results with that one too.

Answer 1

In a situation where the cashier has yet to reach for the tape or the bag

テープでお願いします。

would seem much more appropriate to me.

If they were already reaching for bag, then

あ、テープでいいです。

makes sense.

Obviously, the 「あ」is optional, but it can be very effective in alerting the person that you have something to say about what they are doing, or because you forgot, or whatever.

Honestly, unless your intonation is just plain weird, I think timing would be more important than how it's said for this phrase. Of course, you don't want to sound curt though.