"Can anyone please suggest if a weimar flute is good for a 7th grader student for the class work."
I wouldn't suggest any off-brand instruments. One problem in this age is that they can change the names of instruments faster than they can be labeled with bad reputations.
"We had a Armstrong for the 6th grade class and the local store charged $120 for replacing 2pads and tuning."
That seems steep for replacing two pads. Here in Ohio, a pad replacement goes for no more than $25 max. Although other places may charge more, some may charge less.
I'd say that "tuning" is not a good term for much of anything that a repair person does for a flute. It's generic and non-descriptive as to the actual work being done.
"So, we are planning on buying and found a for $110.00 Wonder if this is a reliable instrument!"
I don't know, I'd wonder also and probably rather rely on a different brand. You get what you pay for in music and in education for your child. I'd hate for a parent to think that their child stopped playing in a few months because they weren't suited to flute when the instrument couldn't be kept in working condition. The child probably won't know if their problems are their own playing or the instruments. A decent quality flute goes for about $600-800 USD. ~Retail. You can sometimes buy them a tad cheaper.
~bilbo
N.E. Ohio
<Added>as additional info, if you're inclined to research this and you prefer to spend money wisely:
http://www.jennifercluff.com/flutequip.htm