There are some mistakes in the sentences. "面值..."here is prepositional phrase which should be followed by numerals together to form an attribute, i.e. 面值50的(noun,e.g. 钞票/美元/人民币,etc.). The case it can be a noun is when you want to show how much does a note is worth, like "这张(/钱币)的面值是50元". And you'd better add "吗" at the end of the second one. Secondly, in this case "拿来"is equal to 拿 with "来" omittable in spoken speech. And be careful, the object is different in each sentence. The first one is "me“ with "拿张面值*的人民币" being the supplement, and the second one is just 钱币(could be any kind of note). Thirdly, if you didn't add "吗" to the second one, it 'd express surprise, doubt, kind of things. Don't be frightened by my explanation. Chinese is totally unlike any other alphabetic language. Please don't simple compare English grammar to Chinese one. Secrets lie mostly in word order. I hope others learning Chinese on italki will find my answer helpful to them.

i think 面值should to be 面纸。 拿面纸给我=拿面纸to me 拿来一张面纸=拿面纸to here（for me？for her？for him？we dont know.）

“verb+来/去”is a complement of directions, if the object is something, it can be put before the "来/去”or behind “来/去”，e.g. 他带了一个照相机来。他带来了一个照相机。if the object is place, it only can be put between the verb and “来/去”，e.g. 我到学校去。我们进教室去吧。