So there are a few different places where you can lease Steem power, let's focus on two. The two which I mention have very different methods surrounding pricing so thought it would be useful to cover both. Both of these platforms are well established and I believe are trustworthy, there are a few others which have popped up which I not willing to recommend without trying them before.
First of all, we have blocktrades.us. Blocktrades allows you lease Steem power at a fixed price, you simply enter the amount of Steem power you wish to lease and they will give you a price. Unfortunately, this is no way the cheapest, at least most of the time. There are cheaper ways available such as the method mentioned next. This, however, is not guaranteed and my explanation should provide clarity around this.
A platform which is widely used within Steem is Minnowbooster, Minnowbooser offers a market where you can set the amount of Steem power you wish to lease and at what price, if a potential leaser likes the ROI which you provide your lease will be accepted and the Steem power will be leased to your account, you can set the total number of weeks you wish to lease the Steem power for in your initial lease request.. Whether this is the cheapest very much depends on the current market rate for leasing Steem Power, this is very much set within Minnow booster, but can differ drastically based on the total demand for Steem power leasing. Obviously using this method you have full control of how much you wish to pay and overall if you can find a potential leaser to accept your lease request you'll be able to access it a lower rate. If you wish to visit Minnowbooster you can use the link below:
It's important to mention that if you plan to use the Steem power for a good cause you might be able to contact potential leaser to ask for a discount, however unlikely this may be, you guaranteed not get it if you don't ask.
Overall I don't think there is anywhere which is giving away Steem power at next to nothing, but I believe with the information above you should have everything you need to get a Steem power lease for a price that works for you.
Minnow booster is the cheapest that I know of but you have to wait for someone to accept your bid. A lot of times noone will rent to you.
block trades is more expensive but it is instant and no questions asked.
I would like to recommend https://www.minnowbooster.net/. Bank of @neoxian also offers lease steempower. But my favorite one is minnowbooster.
I have used delegation hub before. it is just like minnow booster but it is smaller and it charges no fees. I have also used blocktrades but it was expensive.
Very many places to rent or buy steem power, especially in blocktrades and Neoxian banks can also buy and rent steem power, here https://blocktrades.us
minnowbooster.net is usually the cheapest but you have to wait for someone to accept your loan request. Or you can go to blocktrades and pay more but it will be there instantly.