my friend wants a 3 tier cake for her birthday shes my bestie so i said sure!.. butttt i haven't ever made bigger then a sheet cake lol

 im going to buy disposable cake trays from the dollar store. they come 2 in a pack i think.

how many do you think i would need?

one round tray (can be cut in half if need be, they are maybe 3 inches or 4 per  tray/cake tray after baked)

so that's two layers technically per one round tray,  but i realize that 3 inches isn't a nice size for one  tier,  it might be too small. 

 what would you all suggest, how many cake layers go into one tier for a semi small to medium size cake only for maybe 25 people if that...  thank you in advance. 

It's not easy to make a 3 tier cake for only 25 people - but you might try this:

9", 6", 3" - with each tier being just 2 layers of cake (tiered cakes usually have 3 - 4 layers, but that would really be a lot of cake). 9" and 6" pans are easy to find, but for the 3" I suggest baking an extra 9" layer, and then using a 3" (or 4" if you want a little bigger) cookie cutter to cut out 2 rounds. Frosting between each layer and on the top and sides of each cake.

You can use either a cake board or a cut out circle of parchment paper for the  6" tier, but just use a cut out circle of parchment paper (or a flattened cupcake liner) under the 3" tier. She can take the top tier off and have it all to herself!

If you're planning on only using the disposable pans - make 2 pans for the 9" (or 8" - some only come in 8") layers. Then bake 2 more for the 6" layers (you'll cut out a 6" circle from each), then just more for the 3" or 4" layers.

It will be a little shorter than a typical tiered cake... but... you're her friend, who made her a cake... that's what will make it perfect! (and sprinkles... add lots of pretty sprinkles ). It's always special when someone makes a cake just for you!

Have fun!

Your question, as written, is very confusing.  I'm not sure what cake trays you are talking about. Generally speaking, a single tier of cake, has 3-4 layers but you can do 1 or 2 if you like.  One 8" round cake that is 4" high will feed 20-25 people.

If you want 3 tiers stacked-that's a lot of cake-no matter what size tiers you make.  Also, you need to know how to support those tiers.  You cannot just stack 3 cakes on top of each other.

Thanks for all the explaining hehe 

the trays I meant are like bigger versions of like takeout  Chinese food containers

the ones where to close them you have to crimp the edges  

dollar stores sell them as " cake pans " aka small silver disposable round trays 

 your right they come 8 inches and about 3/4inches deep

I'm not sure the size exactly.

so what your saying is 6 trays I need !!? @ sweetneddy. 2 -8inch for the bottom tier. 2-6 inch for the middle and the top make smaller so she can keep!!?? 

 I didn't know about put support inside  the cakes to hold them .. Makes sense though 

i read straws and skeweres inside the straws ??

 For the parchment paper that is meant to use a guidance " circle"  when cutting the smaller cakes !!?? 

 Thank you guys again for helping out !!

Wow... 3/4"  is pretty thin... you might need to go up to 3 layers for each tier - or at least for the bottom tier. Does your dollar store sell regular cake pans? The one I shop at does... the round pans are 8"... but about 1 1/2" deep. Not the best quality - but at least as good as a disposable pan.

It's a good idea to use something at the base of the 6"  and 3" tiers, so they don't rest directly on the tier below... you can buy cardboard cake circles at any cake decorating store. You probably won't find a 3" board, but you could just use a flattened cupcake wrapper or a 3" circle of parchment paper. 

You can definitely use straws for support - there are lots of tutorials to show you how to stack the tiers and how to use the straws. Also, be sure to chill the cake before transporting it - that will help to keep it stable.

Oooh, you're talking about the pans you're baking the cakes in.  Sorry, I had no clue what you were were talking about.  I think SweetNeddy gave you some good advice.

 I would suggest that you hit up some youtube videos on how to make tiered cakes and see if it's something you'd like to venture into.  Then you can come up with a specific plan and we'd be glad to help you step by step.