さえ means *even*. I will provide you with some example sentences leveraging “さえ” Ex1: お酒に酔いすぎて真っ直ぐに[さえ]あるけない。 Because I am drunk too much I cannot [even] walk properly. Ex2: 今日は気分が良く、空を飛ぶこと[さえ]出来るような気がする。 Today, I feel so good that I feel like I can [even] fly. Usually さえ and すら are interchangeable. So you can use the same kind of sentence with すら like Ex3. Also you can put すら as even for EX1 and Ex2 as well. They make pretty much the same meaning. Ex3: ２日間なにも食べていなかったので、昨日の残飯で[すら/さえ]おいしく感じる。 [Even] the leftover from yesterday tastes good since I have never eaten anything for 2 days. Hope this helps!

"さえ" is used to emphasize an example that you usually can do or cannot do. That is to emphasize the different current condition or circumstance from the usual, by listing a particular example. To take Poisonous Apple-san's examples; Ex1: お酒に酔いすぎて真っ直ぐに[さえ]あるけない。 Because I am drunk too much I cannot [even] walk properly. => You can usually walk straight, but you cannot at the moment under the influence. Ex2: 今日は気分が良く、空を飛ぶこと[さえ]出来るような気がする。 Today, I feel so good that I feel like I can [even] fly. => You cannot usually fly, but you feel so good that you feel like you can. (imaginary example) Ex3: ２日間なにも食べていなかったので、昨日の残飯で[すら/さえ]おいしく感じる。 [Even] the leftover from yesterday tastes good since I have never eaten anything for 2 days. => You usually don't feel the leftover is tasty, but now you do under the given circumstance. I hope this will help.