as a vegan, i always had low b12 even when supplementing. once i did a completely clean test, no b12 supplements, and the test could not detect any. it was only sensitive down to 75 pmol/L so my result was 'less than 75'. that's very, very bad.
i readily absorbed b12 supplements once i started taking them more seriously. ergo, i did not have pernicious anemia or the associated issues with intrinsic factor production..
i don't think too much b12 hurts, unless you take it at the wrong time of day - if you take high doses in the neighbourhood of 2000 mcg first thing in the morning, it can disturb your night's sleep.
as for b-complex, it takes a lot of b9 and b6 to cause neurological problems. you should be fine taking an extra strength b100-complex per day. in the short term, if you are low across the board, you can take four per day!
my regular family doc orders my zinc tests when i ask for them. i take the requisition to the lab. where i live the zinc testing is covered by provincial health insurance.
if it wasn't and i had to look elsewhere, i would go to a naturopath who can also write lab requisitions. in that case it would not be covered and i'd have to pay for the test. usually tests i've paid for have been in the area of $30-35 per.
luckily zinc supplements are one of the cheaper ones. i hear you re price though. just the other day i spent $77 CDN on four bottles: calcium, zinc, multivitamins, and vitamin E8 complex. last time i had to make a trip it was more like $200 CDN. still, all in all it feels like peanuts compared to the cost of some pharma products out there!
you're right it can be tough - i've had to get help a time or two, that's for sure.. but worth it.
my approach: no meds so far - just nutrient-dense anti-inflammatory whole foods, and supplements where needed
info: www.whfoods.com, www.nutritiondata.com