Iknowalltort

6) The weight of the snake will be needed to gauge whether the correct size of food is being offered.
7) Even if you don't listen to anyone on here, Buy/borrow books. Buy magazines. Read websites- but for the love of god...slap the "expert at the pet store" who offered you "advice". I promise you they are clueless.
8.TAKE ADVICE ON BOARD and take critisism on the chin.
9) LEARN FROM YOUR MISTAKES and you will enjoy the snake AND the lizard for years to come.

my final message: If you caught them in your garden and they are actually wild. Do them a favour.
Release them.
If you REALLY want a lizard/snake, research them until you are able to provide the correct housing/food/life for them, then go to a pet store, run by someone who also knows what they are talking about, and buy one.
Not being mean, just trying to help you and your pets.
(read these posts from bottom to top lol)

4) get each one in their own suitable enclosure. This will need to be secure and ventilated. It may require heating, lighting, UV, thermostats, hides, climbing materials in arboureal species, water bowls, substrate (type depends on species).
5) One the animals are identified you will need to find out the appropriate food stuffs. Depending on the type of gecko you have will depend on the type of food, as some (e.g. Crested geckos) will eat fruit/ crested gecko diet/ crickets etc), others (e.g. leopard geckos) will only require adequate live food. Live food caught from your garden etc is not suitable. It will need to be bought or bred from live food you have bought in. The food may need supplementing with vitamins/calcium.

Okay, just in case you are not a troll, and you ARE serious about co-habiting your snake and lizard in a bin..
1) Find out what kind of gecko you have.
2) Find out what kind of snake you have.
* post pictures if you need identification help*
3) Split them up. It is highly unlikely that their environmental requirements are anywhere near the same as each other.
having any animal in an unsuitable habitat can cause stress and/or illness.
They may harm/kill each other eventually.