That is fine unless you have some problem. With an unofficial contract, it is hard to get people to be responsible/accountable.
For example, illegal subletting, which can leave you stranded without refund. If the real owner decides to get tough.
With a formal contract there is an obligation for some form of due diligence on the part of the agent to ensure that the renter, is legally entitled to do so. If there is a problem there is recourse to government. Ultimately the real estate agent could lose their license. That makes the agent accountable.

We didn't go through an agent, but we looked at the ownership documents and IDs of the owners before handing over the cash.

If you go through an agent then they look for a min 3 month commitment as the landlord must pay the agent (as must you).
Therefore you'll need to put 3 months rent down + 1 month's deposit + agent fee (anywhere from a couple of hundred to a full months rent).
After this initial 3 months you and the landlord will likely be on a sounder footing and I've found so long as they live nearby and can come and check on the place etc, that they are usually willing to accept a month by month payment so long as they believe you'll stay for 3 months or more and promise to give them ample notice when you leave.

Of course this all depends on the landlord, I've had some good ones. I've had some less than good ones.

I've usually just had 2 x copies of the rental agreement on white paper, signed and fingerprinted. This has so far always done the trick in terms of registration and visas and such.

Hi how many months do you want to rent?I found a post that a university student abroad from German want to share his apartment.
Maybe you could contact him.

tieba.baidu.com/p/3833765195

Thanks everyone for the advice so far. I'm going to be renting an apartment with my brother for at least one year so will either try to get the cash together for the full 12 months or see if I can find something more flexible.

It's not even this difficult in Beijing!

If you know the acronym TIC, well TIK is another one ;-)
A lot of things in Kunming are not as simple and straight forward as they are in other tier 2 and even many tier 3 cities. But they are slowly improving. As my old Chinese boss used to say, 'Welcome to the Alabama of China'.

Rents cost much more in Beijing, so there's actually not much difference in upfront money between 3 months in BJ and 12 months in KM, plus agent fee a 1 month rent.

@yankeeOO fair point. I guess I'm lucky at the moment in that I only have to pay rent every month. Not normal though I know.

I have a few days at the end of August to find somewhere so hopefully I'll get lucky.

Hi,Do you want to live in chenggong university city?there are many rooms for renting or sales. It is quiet here,and faraway from the downtown,but it is convenient to take the subway.

@bluppfisk was saying that any contract is valid as long as it has signatures and stamps or fingerprints, but that's only partly true.

The contract doesn't need to be officially registered or approved at some contract bureau in advance, but if it is not formulated in a legal way, it can easily be thrown out as invalid.

Most of the downloadable and print shop contracts I have seen have been fine, but some are not detailed enough to cover things like who is responsible for what kinds of repairs and various contingencies.