I'm aware that when we say things like:
It's a cheap cell phone.
That's a cheapo, throw it out.
It does mean something is clearly of bad quality. But how about when comparing things? for example:
Those shoes are cheaper than these.
That hotel is cheaper than this one.
Does it give the impression of lower quality, too? How subtle is it? Should I avoid it in any case?
Cheap has two meanings.
Cheap is often used to convey low quality. It easily gets attached to any object being described, even if the price is not low at all.
These cheap shoes cost half my paycheck!
It can also mean a price that is lower than expected. In fact, the original meaning of cheap was 'bargain'. To make sure it has this meaning, use the adjective to modify something related to the price and not the item itself.
Look at the cheap price tag on these shoes!
To illustrate, note how the meaning shifts in the following sentences:
I bought a cheap laptop.
I bought a laptop for a cheap price.
The 'low quality' connotation is minimized when 'cheap' becomes the comparative adjective, 'cheaper'. It imparts some context that it is probably the price of two items you are comparing. However, because you are not stating clearly that it is the price that is cheap, it still conveys a the possibility of low quality.
I know you've already accepted an answer but I would still like to offer what little wisdom I have.
Context is definitely huge when dealing with the word cheap
In order to illustrate this, please see the examples below:
Guy1: Should we fly directly to Miami?
Guy2: Nah, let's catch the flight to West Palm and drive down; the flight is much cheaper.
Guy1: Cool, which hotel should we get.
Guy2: Whichever one is cheaper, but not too cheap.
You are in a store and you overhear:
Wow, these shoes are cheap.
versus
Wow! These shoes are cheap!
versus
Wow! These shoes are inexpensive!
Husband: Which water heater should we buy to replace the old one?
Wife: I'd say this one; it is much more affordable.
Husband: No way! Haven't you heard of how cheap that brand is?! We'll pay the extra $100 and save ourselves a headache.
You invite your friend to the baseball game this weekend and they say:
I'd love to but only if we get cheap-seats.
versus
I'd love to but I can only get budget-friendly seats.
Yes, avoid it, preferably. My mother tongue is not English, but I have been told by a British person that - at least to him - "cheaper" did have a negative connotation. After all, English is spoken by hundreds of millions of people, and not all speakers get the same meaning from the same words, so even when somebody feels no negative flavour in a word, chances are that somebody else feels it. So, when you mean "less expensive", just say "less expensive": this doesn't lend itself to confusion.
It doesn't necessarily give the impression of lower quality. It really refers to the price. Some X shoes might cost 100$ and some Y shoes cost 80$. If the X shoes are on sale and drop the price to 70$, that doesn't mean that the quality is lower than that of the Y shoes that cost 10$ more.
But it might actually imply that the cheaper shoes are not as good as the expensive ones. Really depends on the context; I don't think there is a definite answer.
I don't even feel like the two senses in which it describes a product are different denotatively. They might be listed as two definitions provided in a dictionary but if you look at them they mean the same thing: inexpensive.
The thing is that while the adjective technically modifies one noun, what you're actually describing is something else that's closely related to it.
Look at these great shoes I bought. They were cheap too!
What you're actually describing is the price tag on the shoes. The shoes are the same regardless of the price tag.
I bought these last month and they're already falling apart! What cheap shoes!
Here, what you're describing is the manufacturing of the shoes. It was low-cost, inexpensive (in other words, cheap) manufacturing. The low quality of the shoes has allowed you to infer that the manufacturing was cheap.
If you call a person cheap, it's again the same denotative meaning, but again is applied to something else that's closely related to the person--the kinds of products they buy.
But there's also a different sense that is similar but not quite the same, when you're discussing effort rather than resources. Examples are as in cheap tactics or taking cheap shots.
Generally there's no expense monetarily but it's still similar in that what's being described produces results for little effort.
