Bells & whistles tend to come with any machine other than the little things that run under $100.

The singer that came with the cams I sewed on for 20 years, that model was a good one, as of now, I think you are right they experiment on things, I bought their Futura last year, it has a lot of bells, but I see things that I wish were different, guess there is no one machine that is a dream, that must be why each year new models appear. Rene

Find the local sewing machine repair guy and see if he has any old, simple machine for sale. Some folks just don't pick them up when they get notified.

I'm not sure about the portable part (I find all 'portable' machines quite heavy) buy Husqvarna Viking make a budget range of machines - no electronic screens and such, just the basics. I'd be surprised if they weren't quality machines.

I can't give you the name of the range, they are branded slightly differently in Europe, but if you have a look at their website....

Hope you find what you need,
AJ

Here is a link that might be useful: Husqvarna Viking

You may want to look into a Janome Jem. Lots of people in my quilt guild have them and love them. I just got a Janome 3050 that has some bells and whistles but so far I am very happy with it. (I also have a featherweight that I prefer to do my straight stitching on).
Lots2do