Q: Is the salary negotiable?
Yes, it is,
because principle investigators have some discretion
about how to use their research funding.
Let me illustrate this point by sharing my experience.
A few years ago, I applied for a postdoc at a Canadian university.
I was originally offered a stipend of 36K CAD.
After speaking to the principle investigators,
they decided to increase the stipend to 38K,
and to pay for my medical insurance,
which brought the total to about 40K.
(I suspect that the reason they increased the offer is
that they learned that I was married with kids,
and my wife was not working,
so they were compassionate.
However, they did not explicitly state why they increased the offer,
so take this only as my best guess.)
Q: Are moving expenses covered?
Maybe. You need to ask.
It also depends on the type of postdoc.
It can depend on what type of postdoc opportunity you have.
I had a friend who took a 3-year postdoc at Berkeley
and his job offer included relocation expenses.
In his case, because the job was for 3 years,
it made more economic sense for the job offer to include relocation.
But if your job offer is only for 1 year,
it may not normally include a relocation package.
Incidentally, tenure-track job offers usually include
some amount of relocation allowance.
Q: Can I ask for compensation for parking?
You can definitely ask, but I wouldn't get my hopes up.
If the price for parking is 1000 CAD per year,
it is possible that most students and even some faculty
may take public transport to school.
You should investigate the public transport options.
As a postdoc, I took a bus to and from school every day,
which took at most 30 minutes if there was a long wait.
In fact, at that university,
riding buses was free with a university card,
which was a nice perk.
In the end, I declined the offer from a Canadian university
and accepted a postdoc at another university.
The main reason why I chose a postdoc at another university
is because I felt that the project was more interesting
and a better fit for my skills.
Personally, I did not think that salary was that important as a postdoc.
My mentality as a postdoc was that my postdoc was a temporary position,
useful as a stepping stone to a permanent tenure-track academic job.
While a bigger postdoc salary is nice,
the most I could get might be 5K more a year.
If I instead focused on getting good research experience,
and landing a tenure-track job,
at that point my salary would be at least 80K a year,
which is approximately double my postdoc salary.
If for some reason having a high salary in the short-term
is important to you,
then you shouldn't be looking for postdoc jobs,
or even tenure-track jobs,
because they don't pay that well.
In that case, it may be more expedient to get a job at
a bank, hedge fund, or in consulting,
or even at a company like Google, Microsoft or Apple.