Getting a marker under $850 should be very easy to do!
If you are looking at that price range, go to the nearest field and test shoot some and see what you like. Some love Bob Longs, Planet Eclipse, Macdev, Shockers, Luxes... At that price point it is more about you and not the marker as they are all great.
I purchased a 2k11 G6R and really liked it and then shot a Clone GTI and that's what i have now. I didn't think i'd like a spool valve marker as much as I do but i'm glad i was able to shoot one because it changed my mind. Also always wanted to own a Macdev
That being said, I have a very simple BT-4 Combat for woodsball that i use 75% of the time (D-Day, local events). I knew getting to D-Day or playing woodsball, you will ding your gun on many different things and didn't want to ruin my "fancy speedball gun" haha.
So maybe look at Vanquish 2.0's, Geo 3.5's, Luxes, Clones or Droids, that are used for 500-600 and get you a decent woodsball/scenario marker.
$150 for a tank should be easy to get as well. A used Ninja SL77/4500 is great tank and will be more than enough for what you need.
As for a pod pack, I love my Valken pack i bought off of Amazon for $30. Wish I got the 3+4 instead of the 4+7 but that's besides the point.
Perhaps leave room in the budget for some good paintball pants, Knee pads!!! (worth their weight in gold), jersey, O-ring kits, barrel swab, buy enough pods to fill your pack twice, even a barrel kit is highly recommending if the marker you purchase doesn't come with one.