If your trying to improve your YouTube channel and hope to increase your view count and subscriber count, then giving away free stuff is an interesting way of doing this.
Take my YouTube channel for example, Driver 81 which is an automotive car vlog, and takes you on random adventures in every video. At the time of writing this, I have around 27k subscribers and since making a video about giving away one of my cars, the subscriber count shot upto 100k within months of releasing this video. Take a look at the video here
As you know, most YouTubers exist because they can make money from YouTube, and the more subscribers you have, in theory the greater your income will be. So in this video I had a car that was famous in the channel and was only really worth about £4,000. However by creating this video I was able to significantly increase my subscriber count, which meant i earned way more that I would have got if I had sold the car.
So the answer to the original question is YES, not only is it allowed, but it is also a fantastic way to increase your subscriber count and view count, ultimately meaning you can potentially earn more.
Please feel free to subscribe to my channel, here is another taste of the channel.
Thank you and have a great day. Oh, and please subscribe to my YouTube channel.