I have so many clothes that I don't need. If you want something, come pick out whatever you like.
I have tons of clothes I don't wear. If you're interested, come grab some.
この場合、次のような言い方ができますよ。
ーI have so many clothes that I don't need. If you want something, come pick out whatever you like.
「いらない服がたくさんあるから、欲しかったら好きなもの取りに来てよ」
clothes that I don't need で「いらない服」
to come pick out ... で「…を選びにくる」
ーI have tons of clothes I don't wear. If you're interested, come grab some.
「着ない服がたくさんあるから、興味があったら取りに来てよ」
clothes I don't wear で「着ない服」
come grab ... で「…を取りに来る」
ご参考まで！
I have a lot of clothes I don't need, so if you want them, feel free to come by and take them.
ご質問ありがとうございます。
・「I have a lot of clothes I don't need, so if you want them, feel free to come by and take them.」
（意味) いらない服がたくさんあるから欲しければ家に取りに来てよ
<例文>I have a lot of clothes I don't need, so if you want them, feel free to come by and take them. It's free.
<訳>いらない服がたくさんあるから欲しければ家に取りに来てよ。無料だよ。
参考になれば幸いです。
カナダ 
アメリカ合衆国 
