We know we can connect nouns with the と particle like so:
| 野菜と 魚と 牛乳と 水。 |
| Vegetables and fish and milk and water. |
But the repeated use of と becomes cumbersome when we need to enumerate a long list. We want to say “A, B, C, and so on”. In this case, we use the following structure with the particles や and など.
| 【A】や【B】など |
| A, B, etc. |
| テレビや 冷蔵庫などを 買います。 |
| I will buy a television, a fridge, and so on. |
Contrast this to the sentence which only uses と.
| テレビと 冷蔵庫を 買います。 |
| I will buy a television and a fridge. |
| 数学や 科学など 勉強します。 |
| I will study mathematics and chemistry, etc. |
The object を is very often omitted when など is used.
| ワインや ウイスキーなどの 違いが わかりません。 |
| I don’t understand the difference wines and whiskies. |
とか is the casual way of saying the above. In fact, you will never heard や and など used in conversation (or, at least, very rarely). You will hear とか all the time. What makes とか particularly versatile is that it can be added to just about anything (や can only be used with nouns).
| 牛乳とか パンとか 買う。 |
| I’ll buy milk and bread and other things. |
| 彼女は「うーん」とか「えーと」とか 言う。 |
| She was umming and arring. |
| 岩崎とか 何とか 言う人。 |
| A person called Iwasaki or something. |