Shemiras Shabbos Kehilchasa says a radio is muktzeh machamas chisaron kis. -- I'm allowed to pick up and move a hammer if it's in my way on Shabbos, but not something expensive and delicate like a radio.
Okay that was 40 years ago. What if it's now a $10 radio that I would totally throw out and replace? Has the halacha changed? Has anyone addressed it?
(Similarly he mentions a bolt of fabric -- I suppose it depends on the fabric, but some of those must be cheap today too, no?)
R' Eliezer Melamed, in Peninei Halacha, Shabbat 23:4, sounds similar to your citation from the Shemiras Shabbos Kehilchasa:
Included in this category of muktzeh are: musical instruments, smartphones, radios, tape recorders, expensive or fragile music players, cameras, and mixers. These may not be used even for a permissible purpose, for example, as a paperweight. Similarly, one may not wrap himself in an expensive piece of fabric that has been set aside for sewing. In contrast, a valuable or fragile item that is frequently used on Shabbat, such as a gold watch, eyeglasses, or a magnifying glass for reading, is not muktzeh.
Interestingly, the web version of the original Hebrew of this paragraph opens with a shorter list of devices: "musical instruments, handheld computers, cameras, and mixers."
בכלל מוקצה מחמת 'חסרון כיס': כלי נגינה, מחשב כף יד, מצלמה ומיקסר.
It is notable for the purpose of this question that R' Melamed is a rabbinic authority who is reputed to be particularly in tune with contemporary realities and issues. Indeed, the English website for his Peninei Halacha series ascribes to it "an emphasis on relevant issues which have arisen in the modern era."
If you look closely at the Gemara in which this discussion originates, the svara that the monetary value of an item is what determines its state as "muktseh mechamas chesron kis" (MMC"K) is debunked. I do not have a Gemara on-hand, but if I recall, there was one of the Rabbis (Rava?) who mentioned a gold-maker's hammer, which is quite expensive, and yet the owner does not care much for its becoming dirty at all (lo makpid)!
Rather, the conclusion is that if someone is MAKPID on it as a result of its value to him, that makes it MMC"K.
My rabbi in yeshiva gave a wonderful example of how to determine this. Take for example a smartphone. If the owner is unwilling to let a child play with the phone out of fear that it will get ruined (considering its value...), then that is clearly MMC"K. And if he doesn't mind letting the child with it, he is making it very clear that it is NOT so.
In other words, the criterion is based on the gavra, rather than the cheftsa.
Rav Moshe Zatzal's sevara regarding a blank piece of paper was that nobody would ruin a good, clean sheet of paper, and use it, for example, as a napkin. This Teshuva was written 40 years ago, and things have definitely changed nowadays, and indeed, if a drink would spill, most people would indeed take a fresh, clean piece of paper and use it to wipe the spill, without a thought about "ruining" the paper. Rav Elyashiv Zatzal indeed ruled this way that it is no longer Muktzeh, and Rav Moshe Zatzal would likely agree nowadays as well. Similarly, Rav Elyashiv ruled that a cell phone is Muktzeh as a Kli Shemelachto L'Isur, not as Machmas Chisaron Kis. He did not differentiate between cheap ones or expensive ones, though it is definitely possible that if one has a very expensive one and he is very careful with it and doesn't let his children touch it that it would be Machmas Chisaron Kis for him, but most phone today, even smart phones, are treated the same, and not "off limits" to kids etc., and thus would be Keilim Shemelachtam L'Isur.
Rav Moshe Feinstein in Igros Moshe Orach Chaim 4:72 states that blank paper! is Muktza Machmas Chisaron Kis as a Bar Daas would not use it for anything other than its intended purpose.
It follows that the monetary value of the item is not the determining factor in establishing the Muktza status of the Item.
