Similarly, it's not unusual for my clients to ask for a preapproval letter for much less than the max they "could" do.

I see posts on zillow with an unusually low rent and a lot of contacts, yet still on the market after a long period.  

When you go to get a loan, the lender will want to see the 2 most recent bank statements and they will question anything that looks unusual- a large withdrawal/payment/transfer out of you account might look like a loan payment, which they will want to know about since it will affect your debt to income ratio and how much you can borrow.  

It probably isn't that unusual.2. no laundry in any apartments, and it would be challenging to add hookups;Find a nearby laundromat.

they may need some updating before commanding market rates, maybe not but if it is an unusual building and hasn't been updated you might see some surprizes. 

A contractor I would expect to pay maybe a hundred bucks, assuming you're asking him to ballpark the numbers and not write up a full blown quote.if you see a contractor make sure it is someone who is used to doing rehab s for investors, otherwise the renovation quotes potentially can come in at almost double... for example it is not unusual for a contractor to charge $4000 for a furnace that rehabbers typically spend 2000 for.

The $50k market is very unusual.

It is not unusual to go 5k over budget and sell for 5k less thsn expected.

My 1st year with those sky high interest rates, I only sold 1 house and made $4k. every year my income about doubled except my last year I tripled the year before hitting the $360k but it was an unusual tax driven year. 

It also doesn't seem like a good idea, since you are putting your home on the line in an attempt to make money.Chasing quick appreciation and being fully leveraged puts you in a situation where things can go badly very quickly.It isn't unusual for transaction/holding costs to end up being 10% of the sale price.