Depends on what you mean by "low." At a certain level low enough IQ is associated with intellectual disability, and a difficulty functioning in society. IQ is normalized so half of people have, by definition, an IQ lower than 100, and half have an IQ above 100. 15 points is a standard deviation, so about 68% of people fall between 85 and 115, and the remaining 32% fall within the "tails". I assume by "Low IQ" you would mean the ~16% of the population below 85 IQ, and probably the ~13.5% that fall in the range of 70-85, as below 70 is getting into intellectual disability territory.
Statistically, people in this band do worse in just about every metric for social success. Lower income, higher crime rates, higher rates of drug addiction, poorer health outcomes, etc. However, it is difficult to disentangle these impacts from poverty. Populations' IQs raise when they become less poor, and people regardless of income tend to be less poor if they have higher IQs. The cycle of poverty is deeply intertwined with IQ, and poverty causes a lot of the social issues associated with low IQ. There is a lot of evidence that as access to education and a more "intellectually rich" upbringing increase IQ, and such things are less available to poor people for a variety of reasons.
As for what it's like, from my understanding speaking to people I suspect are in this band the main things are a non-inquisitive world view, a sense of resignation around not understanding abstract concepts, and low self esteem associated with these perceived shortcomings. Society does not treat these people kindly as a whole, and I think that we could all stand to be kinder to one another. I also think that our economic system is geared in such a way that not only are low IQ people punished for that, but they are also made to feel that it is a personal shortcoming even though these things are defined statistically such that there is always a group of people at the bottom who are going to be left behind.