In Star Trek, are food replicators also used by everyday people as a household items? Or is the technology only available to Starfleet?
Replicators are ubiquitous on Earth, not just in Starfleet facilities and on ships.
Miles O'Brien's mother didn't like them. This fascinates Keiko, who was born and raised in Japan.
O'BRIEN: Oh, you'll love it, I promise. I can still remember the aromas when my mother was cooking.
KEIKO: She cooked?
O'BRIEN: She didn't believe in a replicator. She thought real food was more nutritious.
KEIKO: She handled real meat? She touched it and cut it?
TNG: The Wounded
Picard's brother Robert was fighting a running battle with his wife against getting one. Apparently it's been the norm to have one for at least 50 or more years.
ROBERT: Yes, but sadly cooking is becoming a lost art. That's your wretched technology again.
MARIE: Robert and I have had more than a few discussions about getting a replicator in the house.
PICARD: I remember the same discussions between mother and father.
Many (most?) humans have never eaten non-replicated food.
SISKO: (in uniform) Well, my father was a chef. He grew all his own vegetables. My brothers and I were sent out to the gardens every day.
VINOD: Most of the others, they'd only eaten replicated food before they got here. The flavour of the foods we prepare, quite a surprise to them.
SISKO: But not you?
VINOD: My mother would never let me eat replicated food.
The Howard home seen in TNG: Sub Rosa contains an (unseen) replicator, according to the original screenplay.
10 INT. HOWARD HOME - DAY
A large, open living area. The LIVING ROOM is adjacent to a SITTING ROOM... and there are doors to suggest other rooms. There is a stairway leading up to an offscreen second story. The decor should suggest an earlier time and way of life -- a warm Scottish country home from the early 19th century. Herbs and other exotic-looking medicinal ARTIFACTS can be seen throughout the house. And there are a few 24th century devices in evidence -- a replicator, computer terminal, etc.
Reg Barclay has one in his apartment in San Francisco in VOY: Pathfinder. He is, however, not an "everyday person" given that he's a Starfleet officer (who's also an engineer) but it looks like it's a built-in unit, and hence worthy of mention.
BARCLAY: Thanks. One scoop of chocolate ice cream [Replicator Sound]
Replicators appear to be in widespread use throughout the Federation, and in many civilizations outside the Federation regardless of their enlistment in Starfleet.
In the Star Trek: The Next Generation episode "Family", Picard's brother, who is a farmer of a vinyard, and definitely not in Starfleet, says that he refuses to use a replicator, so logically that means that in fact it is normal for people on Earth to rely on them whether or not they are in Starfleet.
There are also surely various other episodes where you can see the use of a replicator by those not in Starfleet (nor working in a Starfleet facility, as is the case with Quark). One episode that jumps to mind is the Star Trek: The Next Generation episode "The Survivors", where Picard and Worf actually give a replicator to the only apparent survivors on Rana IV, who are civilians, and definitely not members of Starfleet.