ANSWER - An eminently sensible question which shows wisdom beyond your years. Sometimes even experienced witches need the reminder that quick and instant gratification in the form of mind altering chemicals or herbs can be too simplistic a refuge for the mind. That isn't to say that such lotions and potions don't have their place in the craft - they do - but for the serious magical practitioner flying ointments are as much about building up a relationship with the entheogenic elements as they are about flipping a switch to alter the state of mind.
So if we discard all chemical drugs, baneful herbs, anything that might not be legal to take/grow in the region where you live and anything that may cause harm (nutmeg for example) what are we left with? Well I have three suggestions - all of which would be considered perfectly legal.
Possibly even more powerful than anything you could ingest are the chemicals your own body is capable of producing. The "fight or flight response" in humans, triggered by a situation in which the person feels fear produces endorphins which (and I'm quoting the wiki) produces a "morphine-like substance originating from within the body." This is a similar effect to that produced by opiates but much more natural. The science behind this explains to some extent the popularity of rollercoaster rides which stimulate the fear response and consequently the endorphin release. This is something that can be achieved quite easily within your own home - even something as simple as watching a horror film could promote this affect.
Endorphins are released with exercise which also helps to achieve a "feel good state" (long term exercise can have a beneficial effect on mood in general with some studies suggesting it can be as effective as anti depressants in combating depression). Again this is something you can make work for you in your own home. Run up your stairs a few times to get your heart rate accelerated and then take the headspace into your magical/meditative work.
As many religions will tell you, fasting can be instrumental in altering a mental state. This works on two levels - the psychological in terms of the fact that you are taking a break from focusing on worldly mundane matters like fuelling your body and also on a more spiritual level where by depriving the body of nutrition (in particular blood sugars) you are opening up your mind to an altered state of consciousness. There is an additional school of thought that fasting can also be a sacrifice offered to the Gods in exchange for enlightenment and another view that fasting is a say to cleanse the body and purge it from the effects of food and alcohol (similar to a spiritual detox). Whatever purpose fasting is used for it is undeniable that fasting for a period of 24 hours will have a distinct effect on the mind of the person undertaking the fast.
My final suggestion is something I work with personally, it is using triggers to store and retrieve different states of mind. I think most people do this on a sub conscious level - for example who hasn't heard a song and been transported into the past on occasion? However this can be extended to deliberately seeking out triggers that will bring back favourable and productive states of mind. Two of my own most personal uses of the memory trigger are Vicks vapour rub and Murray mints, both of which take me back to a time in my childhood when everything was possible and I had a child's natural grasp of magic. The smell of these very personal memory triggers brings me to a headspace where I can access the mind state of myself as a child and this can either be a peaceful refuge from the stress of adult life or a useful alternative mental state to use when working magic.
Experiment with the different ideas and please do stick to your belief that there are many ways to manipulate your own mind. Some of the things I have suggested here do take some effort and may not have the quick fix of popping a pill but they have the advantage of being safe and consistent - which is something that can't always be said about herbs and chemicals.