\documentclass{article}
\RequirePackage[letterpaper, margin=1in]{geometry} % 1 inch margins required

% text
\RequirePackage[utf8]{inputenc}
\setlength\parindent{0pt}
\setlength{\parskip}{1em}
\renewcommand{\familydefault}{\sfdefault}

\usepackage{array}
\newcolumntype{P}[1]{>{\raggedleft\arraybackslash}p{#1}}

\usepackage{soul}

\begin{document}
invoice: simple dual galvanostat \\
request date: 2018-11-01 \\
customer: Oliver Williams \\
group: Wickens

\begin{tabular}{
    P{\dimexpr 0.3\linewidth-2\tabcolsep}|
    P{\dimexpr 0.2\linewidth-2\tabcolsep}|
    P{\dimexpr 0.1\linewidth-2\tabcolsep}|
    P{\dimexpr 0.1\linewidth-2\tabcolsep}|
    P{\dimexpr 0.1\linewidth-2\tabcolsep}|
    p{\dimexpr 0.2\linewidth-2\tabcolsep}}
  item & part & rate & count & total & comment \\ \hline
  enclosure & CU-3005-A\_BUD & 9.00 & 1 & 9.00 & \\
  10 K panel mount digi pot & & 3.00 & 1 & 3.00 & \\
  banana socket & & & 4 & & \\
  switch with LED & & 2.00 & 1 & 2.00 & \\
  barrel plug & & & 1 & & \\
  printed board & & 20.00 & 1 & 20.00 & \\
  enclosure feet & & 0.25 & 4 & 1.00 & \\
  foot wire & & 0.25 & 6 & 1.50 & \\
  standoffs & & 0.25 & 4 & 1.00 & \\
  PCB board connectors & & XXX & 4 & XXX & \\
  test points & & XXX & 6 & XXX & \\
  capacitors, tantilum & & XXX & 3 & XXX & \\
  capacitors, electrolytic & & XXX & 2 & XXX & \\
  8 pin machined sockets & XXX & XXX & 5 & XXX & \\
  variable resistor & 3296 series & 3.00 & 3 & 9.00 & \\
  dual OP-AMP & LM358N & 0.50 & 4 & 2.00 & \\
  differential amplifier & INA105KP & 10.00 & 1 & 10.00 & \\
\end{tabular}
parts total: \$XXX \\
XX hours labor (Blaise Thompson): \$XXX \\
total bill: \$XXX \\
billed 2018-11-XX - internal ID XXXX \\

\end{document}
