Clearly you don't want clips, straps, power pedals or anything except hop on it with whatever shoes and ride. Unlike some comments, I see nothing wrong with that, and keep at least one bike that way myself. So you want something aluminum and with good bearings and such. My suggestion would be something by MKS. A bit above many other pedals in basic quality. MKS Sylvan touring pedals suggested by many. Probably cost you around $35 on Amazon or elsewhere.
Now if you wanted more you could get things like MKS Grip King. A long pedal which will cost you about $55 or so. I have some and do like them better. They are bit slippery when damp.
The MKS RMX pedal might be a better choice. Those run about $30-35 too. Something between a touring road bike pedal and a BMX pedal with those screw in spikes.
There are a number of people that make BMX style pedals in almost any price range. Were I doing it now, I would try the RMX above. But some who tour without clipping in and such insist the spiky wide surface of BMX pedals is the thing. Usually very sturdy (though sometimes heavy).
If money is tight, check a bike shop for some take off pedals. Any aluminum pedal should do okay.