My PS1. Yellow when working on my pc. Blue when working on a remote server. Last $ is red when previous command failed, otherwise is green.

.bashrc-coloured-prompt

# Check if we're on a ssh connection
if [ ! -z "$SSH_TTY" ]; then
    pscolor=94 # Yellow
else
    pscolor=33 # Blue
fi

function exitstatus {
    # Manage exit status within the coloured prompt
    if [ $? -ne 0 ]; then
        export PS1="\[\033[01;"$pscolor"m\]\u@\h \t \w\[\033[00m\]\e[31m$ \e[0m"
    else
        export PS1="\[\033[01;"$pscolor"m\]\u@\h \t \w\[\033[00m\]\e[32m$ \e[0m"
    fi
}
PROMPT_COMMAND=exitstatus